Commendatory Abbot, an ecclesiastic, or sometimes a layman, who holds an abbey in commendam, that is, who draws its revenues and, if an ecclesiastic, may also have some jurisdiction, but does not exercise any authority over its inner monastic discipline. Originally only vacant abbeys, or such as were temporarily without an actual superior, were given in commendam, in the latter case only until an actual superior was elected or appointed. An abbey is held in commendam, i.e. provisorily, in distinction to one held in titulum, which is a permanent benefice. As early as the time of Pope Gregory the Great (590-604) vacant abbeys were given in commendam to bishops who had been driven from their episcopal sees by the invading barbarians. 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. While the notorious Marozia was influential in Rome and Italy, and during the reigns of Henry IV of Germany, Philip I of France, William the Conqueror, William Rufus, Henry I and II of England, the abuse reached its climax. The most worthless persons were often made commendatory abbots, who in many cases brought about the temporal and spiritual ruin of the monasteries. When in 1122 the dispute concerning investiture was settled in favor of the Church, the appointment of laymen as commendatory abbots and many other abuses were abolished. The abuses again increased while the popes resided at Avignon (1309-1377) and especially during the schism (1378-1417), when the popes, as well as the antipopes, gave numerous abbeys in commendam in order to increase the number of their adherents.
After the eighth century various attempts were made by popes and councils to regulate the appointment of commendatory abbots, still the abuses continued. 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 (c. 15, VI, De elect., 1, 6). Clement V (1305-14) revoked benefices which had been granted by him in commendam at an earlier date (Extr. comm., c. 2, De prieb., 3, 2). The Council of Trent (Sess. XXV, cap. xxi, de Regularibus) determined that vacant monasteries should be bestowed only on pious and virtuous regulars, and that the principal or mother-house of an order and the abbeys and priories founded immediately there from should no longer be granted in commendam. The succeeding Bull "Superna" of Gregory XIII, and the Constitution "Pastoralis" of Innocent X greatly checked the abuses, but did not abolish them entirely. Especially in France they continued to flourish to the detriment of the monasteries. Finally, the French Revolution and the general secularization of monasteries in the beginning of the eighteenth century destroyed the evil with the good. Since that time commendatory abbots have become very rare, and the former abuses have been abolished by wise regulations. There are still a few commendatory abbots among the cardinals, and Pope Pius X is Commendatory Abbot of the Benedictine monastery at Subiaco near Rome. The powers of a commendatory abbot are as follows: If the monastery is occupied by a religious community where there is a separate mensa abbatialis, i. e. where the abbot and the convent have each a separate income, the commendatory abbot, who must then be an ecclesiastic, has jurisdiction in faro externo over the members of the community and enjoys all the rights and privileges of an actual abbot, and if, as is generally the case, the monastery has a special superior, he is subject to the commendatory abbot as a claustral prior is subject to his actual abbot. If there is no separate mensa abbatialis, the power of the commendatory abbot extends only over the temporal affairs of the monastery. In case of vacant monasteries the commendatory abbot generally has all the rights and privileges of an actual abbot.