A commendatory abbot (Latin: abbas commendatarius) is an ecclesiastic, or sometimes a layman, who holds an abbey in commendam, drawing its revenues but not exercising any authority over its inner monastic discipline.
[2] Pope Gregory the Great (590–604) on various occasions gave vacant abbeys in commendam to bishops who had been driven from their episcopal sees by invading barbarians or whose own churches were too poor to furnish them a decent livelihood.
[1] The practice began to be seriously abused in the eighth century when the Anglo-Saxon and Frankish kings assumed the right to set commendatory abbots over monasteries that were occupied by religious communities.
Often these commendatory abbots were laymen, vassals of the kings, or others who were authorized to draw the revenues and manage the temporal affairs of the monasteries in reward for military services.
[2] Boniface VIII (1294–1303) decreed that a benefice with the cure of souls attached should be granted in commendam only in great necessity or when evident advantage would accrue to the Church, but never for more than six months.
The Council of Trent determined that vacant monasteries should be bestowed only on pious and virtuous regulars, and that the motherhouse of an order, and the abbeys and priories founded immediately from it, should no longer be granted in commendam.