When the Seljuks commenced their conquest of Anatolia from 1071 onwards, they
began settling their new lands with Turkish tribes from further east.
When the Seljuk Empire weakened and began to fall apart in the
thirteenth century, numerous small Turkish principalities sprang up, one of
which was the Ottoman Beylik in northwest Anatolia. The Ottomans expanded
rapidly as they conquered additional lands from the Byzantines.