Sökmen captured the nearby settlements to the north and west of the Lake Van and increased his power of influence. His most successful conquest is the conquest of Silvan. In 1109 he suffered a defeat by the Armenian local ruler Kogh Vasil who held territory around Raban and Kaysun. Sökmen was always loyal to the Seljukid sultan Mohammad I Tapar and participated in the campaigns of the sultan. Mohammad in turn granted Ahlat to Sökmen as an ikta in 1110. Thus this date is now considered to be the date of the establishment of Ahlatshahs Beylik. In some documents the name of the beylik is "Sökmenli" referring to Sökmen.