Prior to the Roman conquest, Britain was home to about 30 indigenous tribes. The largest were the Belgae, the Brigantes, the Silures and the Iceni. Historian Edward Gibbon believed that Spain, Gaul and Britain were populated by "the same hardy race of savages", based on the similarity of their "manners and languages." The Roman conquest, beginning in 43 AD, and the 400-year rule of southern Britain, was followed by an invasion by Germanic Anglo-Saxon settlers, reducing the Brittonic area mainly to what was to become Wales, Cornwall and, until the latter stages of the Anglo-Saxon settlement, the Hen Ogledd (northern England and parts of southern Scotland). Most of the region settled by the Anglo-Saxons became unified as the Kingdom of England in the 10th century. Meanwhile, Gaelic-speakers in north-west Britain (with connections to the north-east of Ireland and traditionally supposed to have migrated from there in the 5th century) united with the Picts to create the Kingdom of Scotland in the 9th century.