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Post by Admin on Feb 13, 2023 17:53:28 GMT
Three years of extreme drought may have brought about the collapse of the mighty Hittite Empire around 1200 BCE, researchers have said, linking the plight of the fallen civilization to the modern world’s climate crisis. The Hittites dominated Anatolia in modern-day Turkey for nearly 500 years, even rivaling the power of the Egyptian Empire for a period. The Hittites are mentioned dozens of times in the bible, living in and near the land of Canaan during the time of Abraham. The latter purchased a burial cave in Hebron for his wife Sarah from a Hittite man, his grandson Esau was married to Hittite women and Uriah the Hittite was an elite soldier in King David’s army. They were one of several influential ancient civilizations in the Eastern Mediterranean and Near East which were all toppled or severely weakened at around the same time, bringing the curtain down on the Bronze Age. The Hittites mysteriously abandoned their capital and religious center Hattusa around 1200 BCE, when the royal line died out and written historical documents dried up. The empire’s centuries-old political and cultural structures ended “quite rapidly,” Sturt Manning, an archaeologist at Cornell University in the United States and lead author of a new study, told AFP. There are several theories for what was behind the “Late Bronze Age collapse,” including attacks from naval raiders called the “Sea Peoples,” epidemics and famines — as well as a 300-year change to a drier, cooler climate. But exactly what triggered the demise of these empires has remained unclear. ‘Existential threat’ Now, for the Hittites at least, the answer may have come inscribed in the rings of ancient juniper wood. The juniper comes from one of the world’s oldest wooden structures, found at the Phrygian capital of Gordion in central Turkey as part of the excavation of a king’s tomb in the 1950s. By analyzing the rings of the juniper wood, the researchers were able to reconstruct climate conditions more than 3,000 years ago. In semi-arid Central Anatolia, “the major threat to growth for most plants in the region is a lack of water,” Manning said. Narrower tree rings indicate drier years, when a lack of water meant the trees did not grow much. The rings showed three-straight years — 1198 BCE to 1196 BCE — with “unusually” low growth, suggesting a prolonged and particularly severe drought, according to the study published in the journal Nature on Wednesday. The researchers suggested that the drought caused severe food shortages, particularly for the land-locked parts of the central Hittite kingdom, which depended on grain and livestock. The food shortages could have led to political, economic and social unrest, ultimately bringing about the end of the empire. Manning warned that current global warming means the modern world could face a “multi-year existential threat” similar to the one that affected the Hittites. Muge Durusu-Tanriover, an archaeologist at Temple University in Philadelphia who was not involved in the study, hailed it as “groundbreaking.” “Now that we know a major climate event might have tipped the Hittite empire beyond its point of no return, there are more questions to ask about climate change, its impact on states and society and, most crucially, what can be learnt from the past during our current climate crisis,” she said in a Nature comment piece. Severe multi-year drought coincident with Hittite collapse around 1198–1196 BC Sturt W. Manning, Cindy Kocik, Brita Lorentzen & Jed P. Sparks www.nature.com/articles/s41586-022-05693-y
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Post by Admin on Feb 16, 2023 18:41:20 GMT
Severe multi-year drought coincident with Hittite collapse around 1198–1196 BC Sturt W. Manning, Cindy Kocik, Brita Lorentzen & Jed P. Sparks Nature (2023
Abstract The potential of climate change to substantially alter human history is a pressing concern, but the specific effects of different types of climate change remain unknown. This question can be addressed using palaeoclimatic and archaeological data. For instance, a 300-year, low-frequency shift to drier, cooler climate conditions around 1200 BC is frequently associated with the collapse of several ancient civilizations in the Eastern Mediterranean and Near East1,2,3,4. However, the precise details of synchronized climate and human-history-scale associations are lacking. The archaeological–historical record contains multiple instances of human societies successfully adapting to low-frequency climate change5,6,7. It is likely that consecutive multi-year occurrences of rare, unexpected extreme climatic events may push a population beyond adaptation and centuries-old resilience practices5,7,8,9,10. Here we examine the collapse of the Hittite Empire around 1200 BC. The Hittites were one of the great powers in the ancient world across five centuries11,12,13,14, with an empire centred in a semi-arid region in Anatolia with political and socioeconomic interconnections throughout the ancient Near East and Eastern Mediterranean, which for a long time proved resilient despite facing regular and intersecting sociopolitical, economic and environmental challenges. Examination of ring width and stable isotope records obtained from contemporary juniper trees in central Anatolia provides a high-resolution dryness record. This analysis identifies an unusually severe continuous dry period from around 1198 to 1196 (±3) BC, potentially indicating a tipping point, and signals the type of episode that can overwhelm contemporary risk-buffering practices.
Main The vast Hittite Kingdom and subsequently Empire, based in central Anatolia, Turkey, with its capital at Hattusa, is recognized from both rich archaeological remains and textual sources as one of the major Old World powers of the Eastern Mediterranean and Near East between 1650 and 1200 BC. At its apex, the Hittite Empire maintained control over central, southern and southeastern Anatolia, the northern Levant and northern Syria, with almost all of Anatolia being under the Hittite sphere of influence (Extended Data Fig. 1). During this time, the Hittite Empire vied with the Egyptian Empire for sociopolitical dominance in the Near East, a struggle that culminated in the largest battle of the era at Kadesh in Syria in the early 13th century BC15.
Around or shortly after 1200 BC, the Hittite Empire and central administrative system collapsed in a great realignment that reverberated around the Near East4,11,12,13,16,17,18,19,20. The reign of the last known king, Suppiluliuma II, began around 1207 BC and included claimed victories against several intra-Anatolian rivals (Wiyanawanda, Masa, Lukka and Ikkuna) and Alashiya (Cyprus) in sea and land battles, but no further Hittite rulers were recorded subsequently. An inscription of the Egyptian ruler Ramesses III—approximately dated to 1188 BC or 1177 BC, depending on selection and debate in Egyptian history and chronology—lists the Hittites among those swept away by the ‘Sea Peoples’ before they attacked Egypt4,11,17,18.
The end of settlement at Hattusa itself has been a key topic of historical scrutiny. Long considered a victim of attack, whether by the Sea Peoples or local Anatolian raiders, archaeological investigations now indicate that the city was abandoned and emptied by the royal administration and only later burnt11,12,16,21,22,23. Hattusa was the centripetal political and core religious venue of the Hittite gods and kings for centuries, and the reasons for its abandonment remain unclear. The Hittite central sociopolitical and economic system withstood multiple, diverse crises during its tenure: intra-Anatolian tensions with Kaska invaders, rivalries and tensions among constituent elements of the Empire (Arzawa-Mira, Tarhuntassa and Karkemish), dynastic politics (rivals and usurpers to the Great King), and threats such as plague, as well as external challenges, are regularly evident in the Empire’s history11,12,13,14,15,16,21,22,23,24,25. However, the final collapse and abandonment of Hattusa and the central Hittite administration (and thus the cessation of written historical documents) was different and seismic in its scale of impact. Despite evidence of adaptation and continuation of elements of Hittite political and cultural systems at various loci within former Hittite territories (especially in the southeast and in northern Syria)26,27,28, it is undeniable that the succeeding neo-Hittite states that emerged were of a very different, much smaller scale and character19,24,25,26,27,28,29. As Middleton recently stated regarding Hattusa’s collapse: “A context of conflict was nothing new … and so it seems appropriate to conclude that something historically specific (and perhaps never recoverable) happened to precipitate the abandonment”22.
Recent scholarship inspired by contemporary concerns around climate change has increasingly shifted from explaining the fall of the Hittites and the wider collapse of several Late Bronze Age civilizations with invaders or raiders, earthquakes or various political–economic changes as prime movers, to speculate instead on a possible underlying climatic or environmental driver1,2,3,4,11,30,31. Such work cites a variety of palaeoclimatic proxy evidence indicating a probably drier and cooler regime in the Eastern Mediterranean–Anatolian–Near East region in the period from the 13th to 10th centuries BC. However, this evidence is often only loosely placed in absolute temporal terms20 and provides a record of (at best) low-frequency climatic change. In the Hittite case, drought, famine, reduced harvests and concomitant reductions in workforce and military strength might be suggested as possible explanatory structures32, mirroring drought as the main threat to agriculture and food security in Anatolia in more recent history33,34,35,36. Several texts from the 13th century BC refer to apparent grain shortages or famine in Hittite lands. However, the interpretation of this material lacks detail and context20,37, whereas other critical assessments of the data from 13th century BC Hattusa do not necessarily indicate pending crisis38. Nonetheless, it may be observed that the Hittite Kingdom and especially its main centre, Hattusa, engaged in major landscape clearance39 (resulting in soil erosion) and specialized pastoralism40, and relied on higher-risk subsistence strategies dependent on water. Cereal agriculture both locally and from its periphery supplied the necessary large volumes of grain—attested in the early Hittite period by the discovery of a vast storage silo and subsequently via additional, smaller, dispersed silos41. In combination, these linked strategies may have increased production but amplified risk. As in several other early agrarian states, cereals formed a key subsistence and tax base42; in reverse, such states would have been vulnerable to serious and sustained threats to their cereal (and other crop) harvests and animal husbandry.
However, absent from such Late Bronze Age environmental resilience and sustainability assessments are nearly absolutely dated and highly resolved (that is, annual-scale) climate indicators for this region generally, and specifically from the Hittite administrative core in central Anatolia, capable of defining the nature of any critical climatic forcing potentially relevant to the collapse of the core Hittite administrative centre at multiple temporal scales. Gradual, low-frequency, shifts in climate whose amplitude does not completely alter the area’s bioclimatic system—that is, the shift attested in existing palaeoclimate archives for the period1,2,3,4,30,31,43—are less likely to undermine human strategies based around adaptation and resilience (through a wide variety of strategies of diversification, storage and social networking5,6,7,8,44). Similarly, one-year droughts (or comparable high-frequency challenges) are expected, particularly in a semi-arid region such as central Anatolia, where periodic and even regular droughts are anticipated as the main threat to agriculture8,10,33,34,35,36,44. Traditional farming practice (and storage strategies) in the greater Mediterranean region, and most agrarian cases, is adapted with the aim to be able to cope with one bad year5,8,9,10,34,44. What breaks the system—turning regular instances of food scarcity into famine and crisis—is multiple, consecutive harvest failures over two and especially more years5,9,10,44. On the basis of various records from the past several hundred years, such multi-year consecutive serious droughts leading to prolonged harvest reduction and failure (and so famine and associated threats from disease to violence) are rare but probably of potential historical relevance in central Anatolia10,33,34,35,36,37,45,46. Recognition of such critical episodes requires annually resolved data that facilitate multi-scalar (including high-frequency) climatic assessments. Here, high-resolution tree-ring records from central Anatolia enable us to examine climate change in the Late Bronze Age in decadal to multi-decadal generalities, but also with annual-scale and historical specificity. We use data derived from nearly absolutely placed tree-ring time series—both ring-width based and from 13C stable isotope analysis—to characterize an annually resolved climate record of moisture availability for the period around 1500–800 BC and investigate whether there was a catastrophic continuous multi-year drought episode of historical relevance across central Anatolia around 1200 BC.
Juniper ( Juniperus excelsa and Juniperus foetidissima) timbers recovered from archaeological excavations at the site of Gordion in central Anatolia, about 230 km west of the Hittite capital Hattusa near the western frontier of the land of Hatti (the core kingdom of the Hittites), provide an annually resolved tree-ring chronology from around 1775–748 (±3) BC that traverses the end of the Late Bronze Age (Extended Data Fig. 2 and Methods). Twenty-three samples, representing around 18 different trees including the year 1200 BC, form a robust tree-ring chronology. Investigations of recent juniper populations in Anatolia and central Asia indicate that trees, especially from lower elevations (like those likely to be used at ancient Gordion), are susceptible to and exhibit reduced growth owing to decreases in late spring–summer precipitation33,46,47,48 (also critical to cereal production in Anatolia). Thus, examination of the tree-ring patterns in the Gordion tree-ring chronology and identification of episodes of substantially reduced growth increments (narrower tree rings)—after removing effects of age-related growth trends and stand dynamics from the series, and in the absence of any indications of fire or insect attack—probably indicates drier years, with extremes marking probable drought episodes critical to agricultural production and subsistence.
We investigated the Gordion chronology, detrending the individual tree-ring width series to derive a maximized climate signal, which we compared with modern analogous climate data for the central Anatolian region (Extended Data Figs. 1, 3–7 and Methods). Taking the lowest 25% of growth values in the Gordion chronology as indicating drier years, these events occur regularly between around 1497 and 797 BC (Fig. 1 and Extended Data Figs. 5 and 8a). For comparison, the Polatlı meteorological station, which offers the nearest modern climate analogue to ancient Gordion (17 km away), records less than 300 mm of annual precipitation for approximately 20% of the period from AD 1929 to AD 2009. Total annual precipitation of 300 mm is regarded as an approximate minimum threshold for a viable wheat harvest44. Only 6.25% of years from AD 1929 to AD 2009 recorded less than 250 mm of annual precipitation, less than the amount generally regarded as the minimum for cereal cultivation in the Near East, and an amount that would probably produce serious harvest reduction or failure44,49. Although regional precipitation values vary, the largely semi-arid central Anatolian region demonstrates overall congruent records or trends (Methods). In particular, recent and historical instances of extreme arid years are usually common to much of the greater central Anatolian or core Hittite region33,35,36 (Extended Data Figs. 6 and 7). Thus, if we regard the relative occurrence ratio of drier years in the recent Polatlı record as indicative for the broadly similar period of the drier later second millennium BC in central Anatolia30, and use the lowest 20% of values as indicating probable substantial reductions in the harvest, then the Gordion chronology contains only 80 or 85 out of 701 years (11.4%–12.1%) that are part of two or more consecutive such dry years. Between 1270 and 1135 BC, when we also have our best sample replication with 10–18 trees per year, there are only six such sets of years. Only 13 or 16 years (1.9%–2.3%) in total are part of two or more consecutive drought years with the lowest 6.25% of values, representing probable serious harvest reduction or failure. Between around 1270 and 1135 BC there is only one interval in these 135 years—1198–1196 BC—with two or more consecutive years in the lowest 6.25% of values (three consecutive years). Further, in the 12-year period from 1198 to 1187 BC, there were between 6 and 8 years (50–67%) in the lowest 20% of values (Fig. 1 and Extended Data Fig. 8a). Smoothing the data with a 28-point Savitzky–Golay filter representing an average human generational timeframe50, the period around this time represents either the driest or second-driest multi-year interval between 1400 and 1000 BC. This extremely dry interval stands out as a probably substantial climate challenge to food production and subsistence in central Anatolia that may have defeated normal strategies and storage provision in the Hittite administrative core. The dates—approximately 1198–1196 BC—are compatible with the historically derived timeframe of Hittite collapse and reorientation4,11,12,13,16,17,18,19,20,21,22,23,32, and lend an historical specificity that is usually lacking in general low-frequency arguments suggesting linkages between climate and history.
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Post by Admin on Feb 17, 2023 21:01:11 GMT
Fig. 1: Proxies of drier to drought climate from three different detrending methods applied to the Gordion tree-ring dataset. a, Tree-ring record from 1497–797 BC (Methods). The driest 25% of years is shown in orange (other 75% of years in green shading); division indicated by black horizontal line; 28-point Savitzky–Golnay (SG) filter is shown. Instances of 2 or 3 consecutive dry to very dry years at various levels are indicated. There are 3 instances of the driest 6.25% of years occurring consecutively (1494–1492 BC, 1198–1196 BC and 871–869 BC). The grey bar indicates the 12-year period from 1198 to 1187 BC with 3 consecutive years from 1198–1196 BC in the lowest 6.25% of all years and with 6 or 7 years (50–58%) in the lowest 20% of values. GOR, Gordion. b, Close-up of the period 1275–1125 BC, showing annual ARSTAN (ARS) index values (Methods) highlighting those in the lowest 20% and the lowest 6.25% of values. An alternative approach to recovering proxy moisture availability levels from tree rings at lower elevations in a semi-arid area such as central Anatolia is via 13C stable isotope analysis, with higher δ13C values usually indicating drier conditions. The δ13C is defined as [(Rsample − Rstandard)/Rstandard] × 103, in which Rsample is the ratio of 12C to 13C in the unknown and Rstandard is that same ratio in the internationally agreed-upon standard PeeDee Belemnite (PDB). The δ13C is driven by the gradient of CO2 between the atmosphere and the interior of the tree leaf, which is controlled predominantly by leaf stomata, the leaf apertures that control water loss and CO2 transport into the tree. Therefore, δ13C values fluctuate in response to changing moisture availability. We compare average z-transformed results (where positive values indicate higher δ13C) from a series of 13C measurements on α-cellulose extracted from tree rings of four of the Gordion trees with stable isotope records from the Sofular Cave (northwest Anatolia) and Kocain Cave (southwest Anatolia) for the period 1400–1050 BC (Fig. 2 and Methods). The data show a noticeable gradient towards drier conditions in the later 13th century BC, then probable consistently dry to very dry conditions as exhibited by the Gordion tree rings across the interval 1232–1192 BC with drier spikes from 1222 to 1221 BC and around 1195 BC, aligning closely with ring-width minima (Fig. 1 and Extended Data Fig. 8a). This period of drier gradient matches the timeframe of the ancient texts indicating grain shortages in Hittite lands11,20,37 and peaks around the time of the Hittite collapse, consistent with the tree-ring width analysis. Fig. 2: δ13C record from Gordion tree rings compared with δ13C and δ18O records from Sofular and Kocain Caves, Turkey, and the period referred to in texts mentioning famine or grain shortage in Hittite lands. δ13C and δ18O records from Sofular (bottom) and Kocain (top) Caves compared with the Gordion overall combined average z score δ13C time-series, δ13CCorZ, chronology (middle). The Gordion chronology is also represented smoothed with a 28-point Savitzky–Golnay filter (middle). Z-transformed values greater than zero (drier) are highlighted with orange shading above the line and contrasted with green shading for wetter conditions below the line. Dryness increases towards the top of the graph. Bottom, E indicates the End Hattusha–Hittite Kingdom period during the reign of Suppiluliuma II and before Ramesses III year 8. Bottom, out of 9 contemporary texts that refer to famine or grain shortage in Hittite lands20,37, 4 are from the 13th century BC, 3 are undated but also probably originate from the 13th century BC (orange shading), and 2 are from the end of the 13th century BC (red shaded area). The dashed arrows highlight indications of a drying trend in each record.
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Post by Admin on Feb 18, 2023 17:53:21 GMT
Discussion Critiques of many attempts to associate climate change with specific historical or archaeological shifts have focused on the often simplistic and reductionist logic, noting that there is frequently little consideration of how the climate shift is likely to have affected the relevant human subsistence and wider social, economic and political systems6,7,51. In several cases, the timeframes on one side or the other are not sufficiently highly resolved to enable a discussion of whether a specific correlation might exist—let alone whether such a specific correlation might in fact provide an element of causation20,52. Climate alone does not create or cause history. Rather, it is one of the forces comprising the context (habitus) in which human and other actors and vectors make decisions, interact, live lives and affect their surroundings. Humans, especially those living in semi-arid circumstances, expect both variable weather and year-to-year climate differences, and develop practical and physical adaptations (such as agricultural strategies, storage and water infrastructure) and social life (forms of networking) to create resilience against realistic and anticipated scenarios5,8,34,44.
As noted, the Hittite Empire and its core were accustomed to drought threat or stress. Evidence of military installations and political iconography point to efforts to manage territory and landscape11,12. Major water management infrastructure (such as dams and reservoirs) and their strong ritual associations point to efforts to control water resources and ameliorate deficits53,54. However, as observed for the medieval Middle East, “even well-organized regimes found it hard to cope with long periods (more than two years) of food shortages”55. Such periods were not anticipated. In Late Bronze Age Anatolia, although dry years and droughts were a regular feature, and even pairs of arid years generally (although not always) occurred at least once a generation, major droughts causing serious harvest failure in consecutive years were much rarer, probably occurring only once or at most twice in a century (Fig. 1 and Extended Data Fig. 8a). This is similar to observations from the second millennium AD10,33,35,36,45,46. In this context, the evidence of a serious drought and major harvest reduction in central Anatolia for three consecutive years between 1198 and 1196 BC, towards the end of a period from 1204 to 1192 BC according to tree-ring width data (Fig. 1) or from 1230 to 1192 BC according to the δ13C data (Fig. 2) indicating generally lower moisture, is probably an historically important episode that would have severely challenged existing adaptations and resilience strategies. Large land-locked centres and territories reliant on regional grain production and specialized animal husbandry (such as Hattusa and the core Hittite realm, along with the Empire’s overall subsistence and tax base infrastructure) may have been particularly vulnerable in such circumstances (despite various other loci being able to adapt and survive). Outside a few peripheral maritime or riparian locations, marshalling substantial long-distance shipments of bulk subsistence products—if available—would have been logistically impractical for central Anatolia given the over-land transport technology of this period (over-land pre-modern caravan routes of the region centred on items of low bulk and higher value per unit volume or weight56). Much of the Hittite heartland would have been effectively isolated and forced to survive on local resources, and, consequently, in crisis as these were progressively exhausted across one, then two, and finally three years of consecutive serious drought. Further, textual evidence hints that surrounding entities, and especially some of the maritime linked centres (such as Ugarit)—which had their own difficulties20,37—withheld possible grain shipments, in turn exacerbating crises in Anatolia. Intra-Anatolian conflicts may have been stimulated by struggles for key subsistence resources in and immediately following this period. Such circumstances would further stress underlying political, economic and social fault lines within the Hittite world that had apparently been building during the 13th century BC21,23, and around it, and also provide the context for disease outbreaks. Thus, we propose that these three years, between around 1198 and 1196 BC (and the period from 1198 to 1187 BC), may well mark and form a key part of the circumstances that precipitated the collapse of the Hittite Empire. However, we also must acknowledge that we lack the evidence to establish direct causation. It remains likely that this rare, disastrous climate episode from 1198 to 1196 BC tied in with (or enabled) other, probably human, forces that merit further examination. This drought event thus contributed to, but did not solely cause, the collapse and break-up of the Empire.
The Hittite collapse forms part of a wider set of changes occurring across the Old World around 1200 BC1,2,3,4,17,18,19,20. Climate alone was not the sole cause of these changes; very different histories are evident within the greater region20,57 (Methods). Nonetheless, if we consider the two instances of major back-to-back drought widely attested in Anatolia in the past seven centuries10,36,45,46, alongside data and analysis available from the tree-ring width proxy reconstructions in the Old World Drought Atlas58, we find that such severe drought tends to affect most of the area of the Hittite Empire, albeit with some variation in drought intensity (Fig. 3 and Extended Data Figs. 6 and 7). At the same time, as evident from these cases, other areas in the greater Mediterranean–Near East may well have experienced differing circumstances. Such strong differentials, with decisive adversity affecting an adjacent zone, may have helped to fuel population movements, reorientations of trade and political fragmentation, leading to new political alignments and configurations (and not just blanket collapse), and thus also form part of the explanation for the major regional reorientation in the early 12th century BC in conjunction with severe drought in Anatolia20,57,59.
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Post by Admin on Feb 28, 2023 21:40:55 GMT
Fig. 3: Reconstructed summer dryness levels across Europe and the Mediterranean region around the consecutive major drought years AD 1607–1608 and AD 1927–1928. Climate proxy data from the Old World Drought Atlas58 (http://drought.memphis.edu/OWDA/) derived from tree-ring measurements, showing self-calibrating summer (June–July–August (JJA)) Palmer Drought Severity Index (scPDSI) values (negative values indicate drier and positive values indicate wetter) across the Old World region during and around the consecutive major drought years AD 1607–1608 and AD 1927–1928 (2 consecutive years)10. Our study suggests that there were 3 consecutive drought years from 1198 to 1196 BC in Anatolia. Low-frequency climate change creates long-term general forcing conditions affecting human evolution and strategies of adaptation and resilience. However, it is the potentially critical vulnerability of established human systems to unexpected and consecutive multi-year extremes, with concomitant combinations of stresses, that can break and overwhelm established adaptations and resilience practices—and greatly amplify the effects of high-risk land management practices and degradative land use. This applies in history as well as the present in the face of current climate change. The probable multi-year major drought that we identify occurring from 1196 to 1198 BC in Anatolia offers a salient example. www.nature.com/articles/s41586-022-05693-y
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