What is "doukas"

Doukas, Latinized as Ducas (; feminine: Doukaina/Ducaena, Δούκαινα; plural: Doukai/Ducae, Δοῦκαι), from the Latin tile dux ("leader", "general", Hellenized as [ðoux]), is the name of a Byzantine Greek noble family, whose branches provided several notable generals and rulers to the Byzantine Empire in the 9th–11th centuries. A maternally-descended line, the Komnenodoukai, founded the Despotate of Epirus in the 13th century, with another branch ruling over Thessaly. After the 12th century, the name "Doukas" and other variants proliferated across the Byzantine world, and were sometimes presented as signifying a direct genealogical relationship with the original family or the later branch based in the Despotate of Epirus.

The continuity of descent amongst the various branches of the original, middle Byzantine family is not clear, and historians generally recognize several distinct groups of Doukai based on their occurrence in the contemporary sources. According to Demetrios I. Polemis, who compiled the only overview work on the bearers of the Doukas name, in view of this lack of genealogical continuity "it would be a mistake to view the groups of people designated by the cognomen of Doukas as forming one large family".

Doukas or Dukas (c. 1400 – after 1462) was a Byzantine historian who flourished under Constantine XI Palaiologos, the last Byzantine Emperor. He is one of the most important sources for the last decades and eventual fall of the Byzantine Empire to the Ottomans.