De thematibus

De thematibus is a work by Byzantine Emperor Constantine VII Porphyrogenitus. It is primarily a compilation of older sources detailing the origins and development of the empire's provinces.1

Constantine VII, who reigned from 913 to 959, was a prolific writer whose works offer valuable insights into the Byzantine Empire and its neighbors. His writings, including De thematibus, De administrando imperio, and De ceremoniis aulae Byzantinae, cover topics such as foreign policy, court ceremonies, and provincial administration. The De thematibus specifically focuses on the historical background and evolution of the Byzantine administrative divisions known as themes. These themes were originally military districts that later became the primary territorial and administrative units of the empire.12