"Caesar" or "Kaisar" () was a senior court title in the Byzantine Empire. Originally, as in the late Roman Empire, it was used for a subordinate co-emperor or the heir apparent, and was first among the "awarded" dignities. From the reign of Theodosius I, however, most emperors chose to solidify the succession of their intended heirs by raising them to co-emperors. Hence the title was more frequently awarded to second- and third-born sons, or to close and influential relatives of the Emperor: thus for example Alexios Mosele was the son-in-law of Theophilos (ruled 829–842), Bardas was the uncle and chief minister of Michael III (r. 842–867), while Nikephoros II (r. 963–969) awarded the title to his father, Bardas Phokas. An exceptional case was the conferment of the dignity and its insignia to the Bulgarian khan Tervel by Justinian II (r. 685–695, 705–711) who had helped him regain his throne in 705. The title was awarded to the brother of Empress Maria of Alania, George II of Georgia in 1081.