The Despotate of Epirus was one of the Greek rump states of the Byzantine Empire established in the aftermath of the Fourth Crusade in 1204 by a branch of the Angelos dynasty, the Komnenodoukas dynasty. It claimed to be the legitimate successor of the Byzantine Empire during the subsequent struggle for Constantinople, along with the Empire of Nicaea and the Empire of Trebizond; its rulers briefly proclaiming themselves as Emperors in 1227–1242, during which it is most often called the Empire of Thessalonica.