Sebastokrator, was a senior court title in the late Byzantine Empire. It was also used by other rulers whose states bordered the Empire or were within its sphere of influence. The word is a compound of sebastós and krátōr. The wife of a Sebastokrator was named sebastokratorissa in Greek, sevastokratitsa (севастократица) in Bulgarian and sebastokratorica in Serbian.

Alexios I Komnenos, Latinized Alexius I Comnenus, was Byzantine emperor from 1081 to 1118. Although he was not the first emperor of the Komnenian dynasty, it was during his reign that the Komnenos family came to full power and initiated a hereditary succession to the throne. Inheriting a collapsing empire and faced with constant warfare during his reign against both the Seljuq Turks in Asia Minor and the Normans in the western Balkans, Alexios was able to curb the Byzantine decline and begin the military, financial, and territorial recovery known as the Komnenian restoration. His appeals to Western Europe for help against the Turks was the catalyst that sparked the First Crusade.