One of the Turkish principalities founded in the Eastern Anatolia was Dilmacogullari principality that dominated in the region of Bitlis and Erzen. The founder of this principality was Dilmacoglu Mehmed (Muhammed) Bey) and he was involved in the raids towards Anatolia that was under the domination of the Byzantine together with the Turkmen emirs such as Bekcioglu Afsin, Ahmed-shah, etc. in the period of Sultan Alp Arslan.
Dilmacoglu Mehmed Bey had also joined in the Manzikert war (1071). Then, we have observed the fact that he had been also involved in the conquests of the regions around Aleppo. Pursuant to the capture of Diyarbekir in the year of 1085, the Seljuk forces also captured Bitlis and Ahlat. Bitlis and its environs were left to Mehmed Bey for domination and these regions were given him as feoff (the utilisation of the lands). Therefore, Dilmacogullari principality had been founded. They had firstly been submissive to Kilic Arslan and then to Ermenshah Principality. Afterwards, Togan Arslan had been submissive to Ilgazi from Artuklu principality and he had fought against the Crusades and Georgians together with this ruler.
In the period of Hüsâmeddîn Kurt (1137-1143), Mesud who was the sultan of Iraq Seljuk State had given the regions of Ahlat, Manzikert and Erzen to his brother, Seljuk-shah as feoffs. Seljuk-shah had destroyed this region in the year of 1138 and behaved badly to its people.
In the year of 1192, Begtimur from Ermenshah principality captured Bitlis. Afterwards, the Dilmacogullari Principality dominated in and within the environs of Erzen until the end of the century XIV and it must have disappeared from the stage of the history in the period of Akkoyunlu State.