While Licinius pursued with his army, the fugitive tyrant retreated, and again occupied the passes of mount Taurus; and there, by erecting parapets and towers, attempted to stop the march of Licinius. But the victorious troops, by an attack made on the right, broke through all obstacles, and Daia at length fled to Tarsus. There, being hard pressed both by sea and land, he despaired of finding any place for refuge; and in the anguish and dismay of his mind, he sought death as the only remedy of those calamities that God had heaped on him.
But first he gorged himself with food, and large draughts of wine, as those are wont who believe that they eat and drink for the last time; and so he swallowed poison. However, the force of the poison, repelled by his full stomach, could not immediately operate, but it produced a grievous disease, resembling the pestilence; and his life was prolonged only that his sufferings might be more severe. And now the poison began to rage, and to burn up everything within him, so that he was driven to distraction with the intolerable pain; and during a fit of frenzy, which lasted four days, he gathered handfuls of earth, and greedily devoured it.
Having undergone various and excruciating torments, he dashed his forehead against the wall, and his eyes started out of their sockets. And now, become blind, he imagined that he saw God, with His servants arrayed in white robes, sitting in judgment on him. He roared out as men on the rack are wont, and exclaimed that not he, but others, were guilty. In the end, as if he had been racked into confession, he acknowledged his own guilt, and lamentably implored Christ to have mercy upon him. Then, amidst groans, like those of one burnt alive, did he breathe out his guilty soul in the most horrible kind of death.
Source: Of the Manner In Which the Persecutors Died (New Advent)