Eustathios Kymineianos

Eustathios Kymineianos (; ) was a senior Byzantine eunuch official and admiral under Emperor Alexios I Komnenos (r. 1081–1118).

Biography Eustathios' life is known only through the Alexiad of Alexios I's daughter, Anna Komnene. He first appeared in 1087, when Alexios was hosting the Seljuq emir of Nicaea, Abu'l-Qasim in Constantinople. Despite the peace treaty between the two, Alexios decided to use the emir's absence to erect a new fortress to counter the Turks' recent conquest of Nicomedia. Eustathios was sent with a small fleet laden with materials and builders to construct it. To prevent the Turks from reacting, he treated them with every courtesy and claimed that Abu'l-Qasim himself was allowing this work to proceed, all the while impeding any ships to sail from the coasts of Bithynia and notify the emir. Through this ruse, Eustathios was successful in his task.

He next appeared in 1095 at Tzouroulos, when he took custody of the captured rebel who claimed to be a son of Romanos IV Diogenes (r. 1068–71), and had invaded Byzantium with the aid of the Cumans. Before leading him on to Constantinople, Eustathios had him blinded.

He appeared for the last time in 1107, when Alexios named him, along with Nikephoros Dekanos, governor of Constantinople while the emperor was on a campaign against Bohemond in the western Balkans.