John Doukas (megas doux)

Appointed megas doux, he scoured the Aegean of the fleets of the Turkish emir Tzachas, suppressed rebellions in Crete and Cyprus, and then recovered much of the western coast of Anatolia for Byzantium.

[1][2][3] In 1074, during the rebellion of the Norman mercenary Roussel de Bailleul, John, along with his elder brother Michael, was at his grandfather the Caesar's estates in Bithynia.

[2][5] In 1085, when Alexios recovered the strategically important Adriatic port city of Dyrrhachium from the Italo-Normans who had occupied it, John Doukas was installed as the military governor (doux) of the local province.

John repelled the Serbian incursions from Duklja and inner Serbia, and even, according to Anna Komnene, captured the Dukljan king Constantine Bodin (r. 1081–1101), before restoring him to power as a client of the Byzantine Empire.

[5][7][8][9] Thus John managed to restore order in the region of Albania and Dalmatia, which had suffered greatly during the Byzantine–Norman wars of the previous years.

[11][12] As megas doux, John was tasked with countering the naval threat posed by the Turkish emir Tzachas of Smyrna.

[14][12] The combined Byzantine force laid siege to the capital of Lesbos, Mytilene, for three months, when Tzachas offered to cede the island in exchange for safe passage back to Smyrna.

After this victory, John Doukas reinforced the defences of Mytilene and then led his fleet to recover the islands Tzachas had conquered, before returning to Constantinople.

To avoid conflict and facilitate negotiations, he was given custody of the wife of the Seljuk sultan of Rûm Kilij Arslan I (r. 1092–1107) and the daughter of Tzachas, who had been captured at Nicaea.

From there, he marched to the fortresses of Choma and Lampe, installing Eustathios Kamytzes as governor, and reached Polybotos, where most of the Turks who had survived at Ephesus had fled.