While Christianity thus broke down the contempt with which the master had regarded his slaves, and planted among the latter a principle of moral regeneration which expanded in no other sphere with an equal perfection, its action in procuring the freedom of the slave was unceasing. The law of Constantine, which placed the ceremony under the superintendence of the clergy, and the many laws that gave special facilities of manumission to those who desired to enter the monasteries or the priesthood, symbolised the religious character the act had assumed. It was celebrated on Church festivals, especially at Easter; and, although it was not proclaimed a matter of duty or necessity, it was always regarded as one of the most acceptable modes of expiating past sins. St. Melania was said to have emancipated 8,000 slaves; St. Ovidius, a rich martyr of Gaul, 5,000; Chromatius, a Roman prefect under Diocletian, 1,400; Hermes, a prefect in the reign of Trajan, 1,250.(133) Pope St. Gregory, many of the clergy at Hippo under the rule of St. Augustine, as well as great numbers of private individuals, freed their slaves as an act of piety.(134) It became customary to do so on occasions of national or personal thanksgiving, on recovery from sickness, on the birth of a child, at the hour of death, and, above all, in testamentary bequests.(135) Numerous charters and epitaphs still record the gift of liberty to slaves throughout the middle ages, “for the benefit of the soul” of the donor or testator. In the thirteenth century, when there were no slaves to emancipate in France, it was usual in many churches to release caged pigeons on the ecclesiastical festivals, in memory of the ancient charity, and that prisoners might still be freed in the name of Christ.(136)