A sakellarios (Greek: σακελλάριος) or sacellarius is the title of an official entrusted with administrative and financial duties (cf.
[1] Hence, the sakellarios usually is presumed to have headed a sakellion (or sakella, sakelle), a term that appears in early Byzantine sources with the apparent sense of "treasury", more specifically of "cash", as opposed to the vestiarion that was for goods.
Rather they appear connected with the imperial bedchamber (koiton), bearing court titles such as spatharios or koubikoularios, while some holders of the office were entrusted with distinctly non-financial tasks: Emperor Heraclius (r. 610–641) appointed the sakellarios Theodore Trithyrius to command against the Arabs, and yet another sakellarios conducted the examination of Maximos the Confessor under Constans II (r.
[1] By the time of the Taktikon Uspensky of c. 843, the sakellarios had become a general comptroller of the fiscal bureaux (the sekreta), with notaries reporting to the office holder in each department.
By the late eleventh century the ecclesiastic official took over the supervision of donations to, and the administration of, the monasteries of Constantinople.