If the year of his captivity was 405 or 406, and that of his escape or manumission seven years later (412 or 413), twenty years would intervene between his departure out of the land of his bondage, and his return to it clothed with the character and authority of a Christian Bishop. This interval, longer or shorter, he spent in qualifying himself for Holy Orders or discharging priestly duties at Tours, at Lerins, and finally at Rome. But always by night and day he was haunted by the thought of the Pagan nation in which he had spent his long years of servitude, whose language he had acquired, and the character of whose people he so thoroughly understood. These natural retrospections were heightened and deepened by supernatural revelations of the will of Providence towards the Irish, and himself as their apostle. At one time, an angel presented him, in his sleep, a scroll bearing the superscription, "the voice of the Irish;" at another, he seemed to hear in a dream all the unborn children of the nation crying to him for help and holy baptism. When, therefore, Pope Celestine commissioned him for this enterprise, "to the ends of the earth," he found him not only ready but anxious to undertake it. When the new Preacher arrived in the Irish Sea, in 432, he and his companions were driven off the coast of Wicklow by a mob, who assailed them with showers of stones. Running down the coast to Antrim, with which he was personally familiar, he made some stay at Saul, in Down, where he made few converts, and celebrated Mass in a barn; proceeding northward he found himself rejected with scorn by his old master, Milcho, of Slemish. No doubt it appeared an unpardonable audacity in the eyes of the proud Pagan, that his former slave should attempt to teach him how to reform his life and order his affairs. Returning again southward, led on, as we must believe, by the Spirit of God, he determined to strike a blow against Paganism at its most vital point. Having learned that the monarch, Leary (_Laeghaire_), was to celebrate his birthday with suitable rejoicings at Tara, on a day which happened to fall on the eve of Easter, he resolved to proceed to Tara on that occasion, and to confront the Druids in the midst of all the princes and magnates of the Island. With this view he returned on his former course, and landed from his frail barque at the mouth of the Boyne. Taking leave of the boatmen, he desired them to wait for him a certain number of days, when, if they did not hear from him, they might conclude him dead, and provide for their own safety. So saying he set out, accompanied by the few disciples he had made, or brought from abroad, to traverse on foot the great plain which stretches from the mouth of the Boyne to Tara. If those sailors were Christians, as is most likely, we can conceive with what anxiety they must have awaited tidings of an attempt so hazardous and so eventful.