 At times, the Tayy fought alongside the Crusaders, who had conquered the Syrian coastal regions, including Palestine, in 1098–1100.By the end of the 11th century, the Banu Rabi'ah branch of the Tayy (direct descendants of Mufarrij) and the Mazyadid branch of the Banu Assad were the last influential Arab tribes in Syria and Iraq, with the rest having "disappeared from the political map", according to historian Mustafa A. Hiyari.The tribal distribution in the Syrian and north Arabian deserts had significantly changed by the late 12th century as a result of the decline of several major tribes, the expansion of others, namely the Tayy, and the gradual assimilation of substantial Bedouin population with the settled inhabitants.