His father, who defeated the Siculo-Norman invasion of Byzantium at the Battle of Demetritzes, was killed in 1187 when leading a rebellion against Isaac II Angelos.
[2] Together with John Petraliphas, Michael Kantakouzenos and others, he was involved in the successful plot to replace Isaac with his brother Alexios III Angelos in 1195.
[7] Branas was a leader, under Alexios Aspietes, of the Greek party in Philippopolis in opposition to the rule of the Bulgarian Tsar Kaloyan.
Being an avowed anti-Bulgarian Greek and a native of Thrace, he developed even closer ties with the Latins, who were the only force actively confronting the Bulgarian Tsar.
Choniates states that Branas was elected the leader of Greek troops who had made peace with the Latin regime in Constantinople.
In 1206 Theodore Branas acted as a mediator between Henry of Flanders and the Greeks of Adrianople and Didymoteichon, who were menaced by the Bulgarians and wished to seek Latin protection for their cities.
Branas was given command of the garrison of Adrianople, consisting of local Greek troops and 40 Latin knights, and later unsuccessfully defended Didymoteichon when it was besieged and sacked by Kaloyan (20 August 1206).
The Pactum Adrianopolitanum dating to 1206, records the recognition by Marino Zeno, Venetian Podestà of Constantinople, of the right of "the hereditary ruler and captain, most worthy Caesar, most noble Komnenos, lord Theodore Branas", to govern Adrianople and its territories according to the customs of the Greeks.