In order to remove Demetrios from the capital and its vicinity, Constantine made Demetrios Despot of the Morea, to rule the despotate together with Thomas. Demetrios was granted the despotate's nominal capital, Mystras, and primarily ruled the southern and eastern parts of the despotate, with Thomas ruling Corinthia and the north-west, variously using Patras or Leontari as his capital. During his tenure as despot, Demetrios made some efforts to expand the despotate, seizing the Venetian-held castle of Kastri. With him to the Morea, Demetrios brought a part of the ancient Asen family, which had once ruled the Second Bulgarian Empire. Demetrios married Theodora Asanina, daughter of Paul Asan. Theodora's brother Matthew Palaiologos Asen was appointed as governor of Corinth by Demetrios.
