The first people belived to have inhabited Iceland were Irish monks or hermits who came in the eighth century, but left with the arrival of Norsemen, who systematically settled Iceland in the period circa AD 870-930. No archaeological finds have been found to support this theory about these monks known as Papar in Iceland. The first known permanent Norse settler was Ingólfur Arnarson, who built his homestead in Reykjavík in 874. Ingólfur was followed by many other emigrant settlers, largely Norsemen and their Irish slaves. By 930, most arable land had been claimed and the Althing, a legislative and judiciary parliament, was founded as the political hub of the Icelandic Commonwealth. Christianity was probably adopted in 999. The Commonwealth lasted until 1262, when the political system devised by the original settlers proved unable to cope with the increasing power of Icelandic chieftains.