from the middle of the 5th century. However, this scenario, assuming that the Anglo-Saxons were just Germanic Ingaevones, has been questioned. Minor migrations theories The traditional view about the numbers of Anglo-Saxons arriving in Britain during this period has been deconstructed. Incoming people uniting with the existing population could explain why the island conquest was as slow and incomplete as it was, and why the island was exposed to external attacks by Danish pirates and Normans, as well as other issues about the population composition. Stephen Oppenheimer's theory Stephen Oppenheimer, basing his research on the Weale and Capelli studies, maintains that none of the invasions since the Romans have had a significant impact on the gene pool of the British Isles, and that the inhabitants from prehistoric times belong to an Iberian genetic grouping. He says that most people in the British Isles are genetically similar to the Basque people of northern Spain and southwestern France, from 90% in Wales to 66% in East Anglia. Oppenheimer suggests that the division between the West and the East of England is not due to the Anglo-Saxon invasion but originates with two main routes of genetic flow – one up the Atlantic coast, the other from neighbouring areas of Continental Europe – which occurred just after the Last Glacial Maximum. He reports work on linguistics by Forster and Toth which suggests that Indo-European languages began to fragment some 10,000 years ago, at the end of the last Ice Age. He claims that the Celtic languages split from the Indo-European earlier than previously suspected, some 6000 years ago. He claims that the English language split from the other Germanic languages before the Roman period, and became the English that was spoken by the Belgae tribes of what is now southern and eastern England, northeastern France, and Belgium prior to their conquest by the Romans, and long before the arrival of the Anglo-Saxon. Bryan Sykes came to fairly similar conclusions as Oppenheimer in his research, which he set forth in his 2006 published book Blood of the Isles: Exploring the Genetic Roots of our Tribal History, published in the United States and Canada as Saxons, Vikings and Celts: The Genetic Roots of Britain and Ireland. In its summary of their article "Who were the Celts?", the National Museum of Wales note, "It is possible that future genetic studies of ancient and modern human DNA may