Around 1210, Theodore was invited by his half-brother Michael I Komnenos Doukas to Epirus, where Michael had founded an independent Greek principality. Michael wanted Theodore's aid, as his only son, the future Michael II Komnenos Doukas, was underage and illegitimate, while Michael's other half-brothers were considered to lack the ability to rule. Laskaris allowed Theodore to leave, but bound him with an oath of allegiance to himself and his heirs. Before going to Epirus, Theodore had married Maria Petraliphaina, with whom he had four children.