sentences:  In 1214 Turkmen tribesmen captured Alexios, Grand Komnenos of the Empire of Trebizond, on a hunting trip outside of the city.The hostage was turned over to the sultan and negotiated his freedom in exchange for Sinop and the vassalage of Trapezuntine territory to the east.The Seljuqs gained an outlet on the Black Sea to match their Mediterranean port at Antalya, and a wedge was driven between the Empire of Trebizond and the Byzantine Empire of Nicaea.