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. Clement V (1305–1314) revoked benefices which had been granted by him "in commendam" earlier. 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". The succeeding bull "Superna" of Gregory XIII and the constitution "Pastoralis" of Innocent X greatly checked "in commendam" appointments but did not abolish them entirely. In spite of various efforts to reform such a system, it continued to plague the monastic orders throughout the centuries.