What empire did the seljuk Turks threaten?

The Seljuk Turks threatened the Byzantine Empire during their expansion in the 11th century. Their military successes, particularly the Battle of Manzikert in 1071, significantly weakened Byzantine control in Anatolia. This not only facilitated the rise of Turkish settlements in the region but also contributed to the eventual fragmentation of Byzantine power. Their incursions marked a pivotal shift in the balance of power in the eastern Mediterranean.