The title of megas domestikos (), the Grand Domestic in English, was given in the 11th–15th centuries to the commander-in-chief of the Byzantine land army, below the Emperor. Its exact origin is somewhat unclear: it is first mentioned in the 9th century, and most likely derives from the older office of domestikos tōn scholōn ("Domestic of the Schools"), with the epithet megas added to connote the supreme authority of its holder, following contemporary practice evident in other offices as well. Both titles appear to have co-existed for a time, with the megas domestikos being a more exalted variant of the "plain" Domestics of the East and the West, until the late 11th century, when it became a separate office and replaced the "plain" Domestics as commander-in-chief. Nevertheless, the office