Daia, on receiving this news, hasted with relays of horses from the East, to seize the dominions of Galerius, and, while Licinius lingered in Europe, to arrogate to himself all the country as far as the narrow seas of Chalcedon. On his entry into Bithynia, he, with the view of acquiring immediate popularity, abolished Galerius' tax, to the great joy of all. Dissension arose between the two emperors, and almost an open war. They stood on the opposite shores with their armies. Peace, however, and amity were established under certain conditions.
Licinius and Daia met on the narrow sees, concluded a treaty, and in token of friendship joined hands. Then Daia, believing all things to be in security, returned (to Nicomedia), and was in his new dominions what he had been in Syria and Egypt. First of all, he took away the toleration and general protection granted by Galerius to the Christians, and, for this end, he secretly procured addresses from different cities, requesting that no Christian church might be built within their walls; and thus he meant to make that which was his own choice appear as if extorted from him by importunity.
In compliance with those addresses, he introduced a new mode of government in things respecting religion, and for each city he created a high priest, chosen from among the persons of most distinction. The office of those men was to make daily sacrifices to all their gods, and, with the aid of the former priests, to prevent the Christians from erecting churches, or from worshipping God either publicly or in private; and he authorized them to compel the Christians to sacrifice to idols, and, on their refusal, to bring them before the civil magistrate; and, as if this had not been enough, in every province he established a superintendent priest, one of chief eminence in the state; and he commanded that all those priests newly instituted should appear in white habits, that being the most honourable distinction of dress. And as to the Christians, he purposed to follow the course that he had followed in the East, and, affecting the show of clemency, he forbade the slaying of God's servants, but he gave command that they should be mutilated.
So the confessors for the faith had their ears and nostrils slit, their hands and feet lopped off, and their eyes dug out of the sockets.
Source: Of the Manner In Which the Persecutors Died (New Advent)