The discoveries at Ras Shamra matter for two reasons. In the first place, in a country in which the existence of Palestine and then Israel highlights the differences between the Arabs and the Jews, Ras Shamra shows how Judaism grew out of – evolved from – Canaanite religion by a natural process that proves the ancient peoples of this small area, Canaanite and Israelite, to have been essentially the same. Second, the existence of writing – and an alphabet – so early, revolutionised thinking about the Bible. Until the excavation of Ugarit, the accepted view was that writing was unknown to the Hebrews before the ninth century BC and that it was unknown to the Greeks until the seventh. This implied that the Bible was handed down orally for several centuries, making its traditions unreliable and subject to embellishment. In fact, writing was half a millennium older than anyone thought.
In classical archaeology, and in palaeontology, the traditional method of dating is stratigraphy. As common sense suggests, deeper layers are older than the layers above them. However, this only gives a relative chronology, helping to distinguish later from earlier. For absolute dates, some independent evidence is needed, like a king list with written dates, or coins with the date stamped on them, or reference in writings to some heavenly event, like an eclipse, the date of which can be calculated back from modern astronomical knowledge. Such information can then be matched to stratigraphie levels. This is of course not entirely satisfactory. Sites can be damaged, deliberately or accidentally, by man or nature. Tombs can be reused. Archaeologists, palaeontologists, and historians are therefore always on the lookout for other dating methods. The twentieth century offered several answers in this area, and the first came in 1929.
In the notebooks of Leonardo da Vinci there is a brief paragraph to the effect that dry and wet years can be traced in tree rings. The same observation was repeated in 1837 by Charles Babbage – more famous as the man who designed the first mechanical calculators, ancestors of the computer – but he added the notion that tree rings might also be related to other forms of dating. No one took this up for generations, but then an American physicist and astronomer, Dr Andrew Ellicott Douglass, director of the University of Arizona’s Steward Observatory, made a breakthrough. His research interest was the effect of sunspots on the climate of the earth, and like other astronomers and climatologists he knew that, crudely speaking, every eleven years or so, when sunspot activity is at its height, the earth is racked by storms and rain, one consequence of which is that there is well above average moisture for plants and trees.45 In order to prove this link, Douglass needed to show that the pattern had been repeated far back into history. For such a project, the incomplete and occasional details about weather were woefully inadequate. It was then that Douglass remembered something he had noticed as a boy, an observation familiar to everyone brought up in the countryside. When a tree is sawn through and the top part carted away, leaving just the stump, we see row upon row of concentric rings. All woodmen, gardeners, and carpenters know, as part of the lore of their trade, that tree rings are annual rings. But what Douglass observed, which no one else had thought through, was that the rings are not of equal thickness. Some years there are narrow rings, other years the rings are broader. Could it be, Douglass wondered, that the broad rings represent ‘fat years’ (i.e., moist years), and the thin rings represent ‘lean years’ – in other words, dry years?46
It was a simple but inspired idea, not least because it could be tested fairly easily. Douglass set about comparing the outer rings of a newly cut tree with weather reports from recent years. To his satisfaction he discovered that his assumption fitted the facts. Next he moved further back. Some trees in Arizona where he lived were three hundred years old; if he followed the rings all the way into the pith of the trunk, he should be able to re-create climate fluctuations for his region in past centuries. Every eleven years, coinciding with sunspot activity, there had been a ‘fat period,’ several years of broad rings. Douglass had proved his point that sunspot activity and weather are related. But now he saw other uses for his new technique. In Arizona, most of the trees were pine and didn’t go back earlier than 1450, just before the European invasion of America.47 At first Douglass obtained samples of trees cut by the Spaniards in the early sixteenth century to construct their missions. During his research, Douglass wrote to a number of archaeologists in the American Southwest, asking for core samples of the wood on their sites. Earl Morris, working amid the Aztec ruins fifty miles north of Pueblo Bonito, a prehistoric site in New Mexico, and Neil Judd, excavating Pueblo Bonito itself, both sent samples.48 These Aztec ‘great houses’ appeared to have been built at the same time, judging by their style and the objects excavated, but there had been no written calendar in North America, and so no one had been able to place an exact date on the pueblos. Some time after Douglass received his samples from Morris and Judd, he was able to thank them with a bombshelclass="underline" ‘You might be interested to know,’ he said in a letter, ‘that the latest beam in the ceiling of the Aztec ruins was cut just exactly nine years before the latest beam from Bonito.’49
A new science, dendrochronology, had been born, and Pueblo Bonito was the first classical problem it helped solve. Douglass’s research had begun in 1913, but not until 1928–9 did he feel able to announce his findings to the world. At that point, by overlapping trees of different ages felled at different times, he had an unbroken sequence of rings in southwest America going back first to ALL 1300, then to ALL 700.50 The sequence revealed that there had been a severe drought, which lasted from ALL 1276 to 1299 and explained why there had been a vast migration at that time by Pueblo Indians, a puzzle which had baffled archaeologists for centuries.
These discoveries placed yet more of man’s history on an evolutionary ladder, with ever more specific time frames. The evolution of writing, of religions, of law, and even of building all began to slot into place in the 1920s, making history and prehistory more and more comprehensible as one linked story. Even the familiar events of the Bible appeared to fit into the emerging sequence of events. Such a view had its dangers, of course. Order could be imposed where there may have been none, and complex processes could be oversimplified. Many people were fascinated by scientific discovery and found the new narrative satisfying, but others were disturbed by what they took to be further ‘disenchantment’ of the world, the removal of mystery. That was one reason why a very short book, published in 1931, had the impact that it did.