Sunday, February 1, 2009
The extent to which the landscape was being farmed and the efficiency of agricultural practices may be measured by the degree of freedom with which settlements drifted. The growth of population and commensurate expansion of settlement is reflected in the increasingly varied soil environments settled through the Anglo-Saxon period. The archaeological evidence suggests that settlements drifted, whether for demographic, agricultural or other reasons, from an initial point and that there was a more severe pattern of relocation that took place between AD 650–750. This occurred at the same time that there was a major dislocation in building traditions (Marshall and Marshall 1993:400). Successive stages of drift can be identified in many settlements that were then abandoned; resettlement may have occurred in the vicinity but not sufficiently close to be detected in the same way as the earlier drift. It may be that settlement patterns began to be more stable, in part, because of the development of land ownership with established property boundaries (Hamerow 1991). The earliest surviving land charters, documents indicating title to property and defining its boundaries, date from the seventh century indicating that some such change was taking place. The pagan Anglo-Saxon cemeteries are much easier to date because of the larger number of artefacts found in them as grave-goods. However, they are a poor indicator of the extent of shifting settlement because there was an inherent conservatism in the location of cemeteries, a desire to continue to place the dead among the ancestors. So while settlements drifted around an original nucleus the cemetery often remained in use. However, very few cemeteries remained in use throughout the period, and those that did tend to be the large examples in mid- and eastern England that may have had a centralised function and were therefore not subject to the effects of settlement drift. There may of course be special reasons for the development of new cemeteries that are distinct from the factors provoking settlement shift but it must be in part a related issue.
The instability of the rural economy may in part be dependent on the effects of climatic change. A global climatic cataclysm began in AD 536  that was to last for about ten years. A thick cloud of dust that blocked out the sun’s heat and light is likely to have been caused by the impact of an asteroid of medium size (Baillie 1994) and resulted in the failure of crops. In the 540s plague swept through Europe. Bede describes how in the 670s the South Saxons were saved ‘from a cruel and horrible extinction as a result of their conversion to Christianity by Wilfrid: Tor no rain had fallen in the province for three years prior to his arrival, and a terrible famine had ensued which reduced many to an awful death’ (Colgrave and Mynors 1969: IV 13). Extreme fluctuations in climate are more likely to have a detectable effect on settlement patterns than gradual changes. There is evidence for a minor advance in European glaciers during the period AD 700–900 (Denton and Karlén 1973). Tooley has demonstrated that there was a period of climatic extremes in addition to a complex marine transgression sequence at this time. Sea-levels rose to a maximum of +1.2 m above sea-level in c. AD 150, falling during the following 500 years to a minimum altitude of +0.4 m above sealevel by c. 650 (Tooley 1978:182–92). Specific examples of the effects of such transgressions have been noted in studies of settlement patterns in coastal and estuarine regions (Hallam 1961; Hawkes 1968; Thompson 1980). The extent of climatic change and its actual effect on human communities is difficult to define but there remain a number of definite possibilities.
With an assumed growing population in early Anglo-Saxon England there would have been increasing pressure on rural resources, especially by the second half of the seventh century. With the development of urban centres and religious foundations greater demand would have been placed on the hinterland. The predictable result would have been an intensification of agriculture and changes in the nature of landholding and ownership. A reflection of this may be the final relocation of settlements on to more fertile and productive soils and the changes in cereal crops being cultivated. An agricultural surplus would have been required to support the development of urban centres which in turn encouraged craft specialisation. In this way the move to more fertile soils may have been made to improve productivity per person and increase output for similar or less effort.
 Holocene impact events have been proposed by the dendrochronologist Mike Baillie as a possible cause of several brief (typically 5-10 year) climatic downturns recorded in ancient tree ring patterns. In his book 'Exodus to Arthur: Catastrophic encounters with comets,' he highlights four such events and suggests that these might have been caused by the dust veils thrown up by the impact of cometary debris.
It was a catastrophe without precedent in recorded history: for months on end, starting in A.D. 535, a strange, dusky haze robbed much of the earth of normal sunlight. Crops failed in Asia and the Middle East as global weather patterns radically altered. Bubonic plague, exploding out of Africa, wiped out entire populations in Europe. Flood and drought brought ancient cultures to the brink of collapse. In a matter of decades, the old order died and a new world-essentially the modern world as we know it today-began to emerge. In this fascinating, groundbreaking, totally accessible book, archaeological journalist David Keys dramatically reconstructs the global chain of revolutions that began in the catastrophe of A.D. 535, then offers a definitive explanation of how and why this cataclysm occurred on that momentous day centuries ago. The Roman Empire, the greatest power in Europe and the Middle East for centuries, lost half its territory in the century following the catastrophe. During the exact same period, the ancient southern Chinese state, weakened by economic turmoil, succumbed to invaders from the north, and a single unified China was born.
David Keys is archaeology correspondent for the London daily paper, The Independent, frequent television commentator on archeological matters and author of the controversial book, Catastrophe: An Investigation into the Origins of the Modern World (1999). He has visited over 1,000 archaeological sites in 60 countries. He was featured as one of the main interview subjects, in the 2000 pilot to the PBS series, Secrets of the Dead, giving insight into subject of the climatic catastrophe, which is the subject of his book.
Keys's thesis in Catastrophe is that a global climatic catastrophe in A.D. 535-536 - a massive volcanic eruption sundering Java from Sumatra - was the decisive factor that transformed the Ancient World into the Medieval Era. Ancient chroniclers recorded a disaster in that year that blotted out the sun for months, causing famine, droughts, floods, storms and bubonic plague. Keys uses tree-ring samples, analysis of lake deposits and ice cores, as well as contemporaneous documents to bolster his speculative thesis. In his scenario, the ensuing disasters precipitated the disintegration of the Byzantine Empire, beset by Slav, Mongol and Persian invaders propelled from their disrupted homelands. The Sixth Century collapse of Arabian civilization under pressure from floods and crop failure created an apocalyptic atmosphere that set the stage for Islam's emergence. In Mexico, the cataclysm supposedly triggered the collapse of Teotihuacán; in Anatolia, it helped the Turks establish what eventually became the Ottoman Empire; while in China, the ensuing half-century of political and social chaos led to a reunified nation. Keys stokes anxieties about future cataclysms by finishing with a roundup of trouble spots that could conceivably wreak planetary havoc.
Critics have accused Keys of oversimplifying history with a "single chain of causality". He has been charged with reassembling history to fit his thesis, "relentlessly overworking its explanatory power in a manner reminiscent of Velikovsky's theory that a comet collided with the earth in 1500 BC" (Publishers Weekly). Nevertheless, Keys worked his treatise with the advice of dozens of academic consultants. Writing in The New York Times Book Review, Malcolm W. Browne insists that "...this book must be taken seriously, if only as a reminder that survival in a world threatened by real dangers hangs by a very slender thread."