Complex sentence: Therefore the sakellarios was also an administrative title; in particular the Sacellarius or "Megas Sakellarios" (Great Sakellarios) was in fact the Finance Minister of the Byzantine Empire.
Split into simpler sentences: Therefore the sakellarios was also an administrative title. In particular the Sacellarius or "Megas Sakellarios" (Great Sakellarios) was in fact the finance minister of the Byzantine Empire.