Within the Church, the rite of the Mass was not completely fixed, and there were places at the end of the Offertory for the "Secret" prayers, when the priest could insert private prayers for various personal needs. These practices became especially prevalent in France (see Pre-Tridentine Mass). As these types of personal prayers within the Mass spread, the institution of the Low Mass became quite common, where priests would hire their services out to perform various Masses for the needs of their clients (Votive Masses) — such as blessing crops or cattle, achieving success in some enterprise, obtaining love, or even cursing enemies (one way this latter was done was by inserting the enemy's name in a Mass for the dead, accompanied by burying an image of the enemy). In the 12th and 13th centuries there was a great surplus of clerics and monks who might be inclined to perform these Masses, as younger sons were often sent off to religious universities, and after their studies, needed to find a livelihood. Also within the Church, the Mass was sometimes reworked to create light-hearted parodies of it for certain Church festivities. Some of these became accepted practices at times, such as a festive parody of the Mass called "The Feast of Asses", in which Balaam's ass (from the Old Testament) would begin talking and saying parts of the Mass. A similar parody was the Feast of Fools.