John Kantakouzenos (sebastos)
He distinguished himself in the campaigns of Manuel I Komnenos (r. 1143–1180) against the Serbians, Hungarians, and Pechengs in the years between 1150 and 1153. It was during these campaigns that he was severely wounded and lost the fingers of one hand. In 1155 he was sent to Belgrade where he foiled the plot of the inhabitants of that city to hand the city over to the Hungarians. He was killed in the Battle of Myriokephalon, where he served as a commander of a division of the Byzantine army. He fell, having been isolated from his own troops, fighting alone against a band of Seljuk Turk soldiers of the Sultanate of Rum.
John is known to have been present at the ecclesiastical councils convened at Constantinople in May 1157, March 1166, and January and February 1170. In the acts of those councils he is described as holding the rank of sebastos, and ranks first in the class of the sebastoi.
John Kantakouzenos was married to Maria Komnene, the eldest daughter of Manuel I's brother, the sebastokrator Andronikos Komnenos. They had at least one son, Manuel Kantakouzenos, who campaigned against the Turks with Andronikos Angelos, but afterwards offended Emperor Manuel I, who put him in prison where he was blinded.
- Nicol, Donald (1968). The Byzantine family of Kantakouzenos (Cantacuzenus) ca. 1100-1460: A Genealogical and Prosopographical Study. Dumbarton Oaks Center for Byzantine Studies.
- Stiernon, Lucien (1965). "Notes de titulature et de prosopographie byzantines: Sébaste et gambros". Revue des études byzantines. 23: 222–243. doi:10.3406/rebyz.1965.1349.