The Tombs of Martyrs and the Cemeteries to be transferred to the Possession of the Churches
Again, with respect to those places which are honored in being the depositories of the remains of martyrs, and continue to be memorials of their glorious departure; how can we doubt that they rightly belong to the churches, or refrain from issuing our injunction to that effect? For surely there can be no better liberality, no labor more pleasing or profitable, than to be thus employed under the guidance of the Divine Spirit, in order that those things which have been appropriated on false pretenses by unjust and wicked men, may be restored, as justice demands, and once more secured to the holy churches.
Source: Life of Constantine (New Advent)