Here he was purchased as a slave by Michul or Milchu, a chief of North Dalaradia, who dwelt in the valley of the Braid, near Mount Slemish, in the country of Antrim. The work assigned him was that of attending his master's flocks and herds, and in his "Confession," which he wrote toward the close of his life, he describes how he wandered over the bleak mountains, often drenched with the rains, and numbed with the frosts. His period of servitude lasted six years; and during this time he would seem to have made himself acquainted with the language of the native tribes, and to have learned their habits and modes of life. At length he succeeded in effecting his escape to the seaside, where he took ship, and, after a tempestuous passage, regained his father's house. His stay, however, was destined to be very short. In a predatory excursion he was a second time taken captive, and again, after a brief interval, succeeded in making his escape.

Had he listened to his parents, he would now have remained with them, but he was bent on a very different occupation. "The Divine Voice," he says, "frequently admonished me to consider whence I derived the wisdom which was in me, who once knew neither the number of my days nor was acquainted with God; and whence I obtained afterward so great and salutary a gift as to know and to love God." During the weary hours, moreover, of his captivity, he had often reflected how blessed a thing it would be if he, to whom it had been given to know the true God and his Son Jesus Christ, could carry the glad tidings to his master's people and the land of his exile.

One night, he tells us, he had a dream, in which he thought he saw a man coming from Ireland with a number of letters. One of these he gave him to read, and in the beginning occurred the words, "The voice of the Irish." While he was reading it, he thought he heard a voice calling to him across the Western Sea, "We entreat thee, holy youth, to come and walk among us."

Obedient, therefore, to what he deemed to be a plain leading from heaven, and resisting the arguments and entreaties of relatives and friends, who mocked at his enthusiastic resolve, he set out for the monasteries in Southern France, there to prepare himself for the work of preaching the gospel in the land of his captivity. Amidst the conflicting legends which now follow him at every step, it seems probable that he repaired to the monastic schools of Tours, Auxerre, and Lerins, where he studied and was employed for some little time in pastoral duties, having been ordained successively deacon and priest.

There, too, he would seem to have been elevated to the episcopate, and thence with a band of fellow-laborers he set sail for Ireland, about the middle of the fifth century. Landing on one of the islands off the coast of Dublin, he and his companions tried unsuccessfully to obtain provisions, which they greatly needed. Thence sailing northward they put in at a strait called Brene, and after landing at the southwestern extremity of Strangford Lough, advanced some considerable way into the interior.

They had not gone far before they encountered a native chief named Dichu, at the head of a band of men. Mistaking St. Patrick for the leader of one of the many pirate crews which at that time often appeared upon the coast, he was on the point of putting him to death. But struck by the missionary's appearance, and seeing that both he and his companions were unarmed, he hospitably received them into his house. In frequent interviews he now heard the doctrines of the faith, and after a time was baptized, with all his family. According to some authorities he also bestowed upon his instructor the ground whereon his barn was built; and here arose the celebrated church called Sabhall Patraic, "The Barn of Patrick," which still retains the name of Sabhal, or Saul, and is situated about two miles northeast of Downpatrick.

Leaving Saul, the missionaries proceeded to northern Dalaradia, and the residence of St. Patrick's old master, Milchu. But nothing would induce the old chief to receive one who had once been his slave, or to forsake the paganism of his forefathers. His journey thus ineffectual, St. Patrick returned to the district where Dichu resided, and made the neighborhood for sometime his headquarters. Thence proceeding southward, he determined to visit the central parts of the island, and especially the famous hill of Tara, where King Laoghaire was about to hold a great religious festival in the presence of all of his tributary chieftains, druids, and bards. In this stronghold of druidism he resolved to celebrate the approaching festival of Easter, and preach the word to the assembled chiefs. It was Easter eve, we are told, when he reached the neighborhood of Tara, and having erected a tent, he made preparations for spending the night with his companions, and kindled a fire for the purpose of preparing food. As the smoke curled upward in the evening air, it was observed by the druids in the king's tents and caused the greatest consternation. To kindle any fire during the solemn assembly of the chiefs, before the king had lighted the sacred flame in the palace of Tara, was a sin of the greatest enormity, and the druids did not scruple to warn the king that if the fire of the stranger was not extinguished that night, unto him, whose fire it was, would belong the sovereignty of Ireland forever.

Messengers were accordingly sent to discover the authors of the sacrilege, and to order them to appear before Laoghaire. The missionaries went, and their fearlessness when in the presence of the monarch and his nobles won for them a respectful hearing. On the following day St. Patrick again addressed the chiefs, doubtless in their own language, and proclaimed to them the doctrines of the faith. Laoghaire himself, indeed, did not profess to be a convert, but he gave permission to the man of God to preach the word, on condition that he did not disturb the peace of the kingdom. During the ensuing week, therefore, when the great public games were celebrated at Tailten, the missionary and his companions addressed themselves to the youngest brother of the king, and were so favorably received that he professed himself a believer, submitted to baptism, and is said to have given the site of a church called afterward "The Great Church of Patrick."