Miriarch (Italian: Miriarca) was the title of a Byzantine personage known only for commanding the troops of the new emperor Constantine X Ducas in 1060 and 1061 in the Catapanate of Italy. Miriarch may have been a name.
Late in 1060, Miriarch led a large army to take Taranto, Brindisi, Oria, and Otranto in a stunning reversal of Norman fortunes. He advanced as far as the walls of Melfi, but his siege was relieved by the arrival of Robert Guiscard, fresh from vanquishing the Moslems in Sicily. Miriarch was succeeded by Maruli in 1061 as Guiscard advanced through Apulia.
- Gay, Jules. L'Italie méridionale et l'empire Byzantin: Livre II. Burt Franklin: New York, 1904.