In the second half of the 13th century, the Seljuks of Anatolia became the puppet of the Mongols and the vassal Turkmen tribes began to act independently.
Mesut was the son of Menteshe, a tribe leader who had settled his tribe in Caria (southwestern Anatolia, presently Muğla Province and parts of Aydın and Antalya Provinces of Turkey).
He controlled most of the beylik except Finike (ancient Phoenicus at the extreme east of the beylik ) which was under his brother's rule [1] In the early years of his reign, he fought against the Byzantine army which tried to recapture the Caria region.
[2] After Byzantine army returned, he began attacking nearby islands by his newly founded fleet.
[dubious – discuss] However, in 1310 Knights Hospitaller recaptured the island with the help of Philip IV of France.