St. Columkille 
From The Wonders of Ireland by P. W. Joyce, 1911
Saint Columkille  was born in the year 521 in Gartan a wild district in the county Donegal not far from Letterkenny. He was a near relation of the kings of Ireland of his time; for his father was great-grandson of the mighty King Niall of the Nine Hostages: and his mother was related to the kings of Leinster. He spent his boyhood in a little village near Gartan; and when he was old enough he was sent away from his home to a school kept by a distinguished bishop and teacher, St. Finnen, at Movilla near the present Newtownards in Down. Though he belonged to a princely family and might easily have become rich and great, he gave up these worldly advantages for religion, and resolved to become a priest.
Having spent some time at Movilla, the youthful Columkille went to several other Irish Colleges, including that of St. Movi at Glasnevin near Dublin; and as he was a diligent student he made great progress in all. The most celebrated of these was at Clonard in Meath, in which there were many hundreds of students under the instruction of another St. Finnen, a great and holy man who is styled in old Irish writings "a doctor of wisdom and the tutor of the saints of Ireland in his time." Here Columkille met many young Irishmen who afterwards became distinguished saints and missionaries.
As soon as he was ordained priest he set about the work of his life—spreading the Gospel. At that time the high ridge over the river Foyle where now stands the old city of Derry, was an uninhabited spot clothed with a splendid wood of oaks from which it got the name of Derry, meaning an oak grove: this spot was presented to Columkille by his cousin prince Aed, afterwards king of Ireland. Here when he was twenty-five years of age (in 546) he built his first church round which grew up a monastery that continued to flourish for many hundred years, so that in memory of the saint the place was long afterwards known by the name of Derry-Columkille. At this period of his life he was a man of noble presence, a worthy member of a kingly race, as one of the old Irish writers describes him:—tall broad-shouldered and powerful, with long curling hair, luminous grey eyes, and a countenance bright and pleasing: and he was always lively and agreeable in conversation.
For fifteen years after the establishment of Derry, Columkille continued to found churches all over the country, among many others those of Kells in Meath, Tory Island, Swords near Dublin, Drumcliff in Sligo, and Durrow in King's County, the last of which was his chief establishment in Ireland. It is recorded that during these fifteen years he founded altogether three hundred churches and monasteries. These establishments, like all the other Irish monasteries, were the means of spreading not only religion but general enlightenment: for in most of them there were schools; and the priests and monks converted and taught and civilised, to the best of their power, the people in their neighbourhood.
Many years before this, St. Patrick and the missionaries who worked under his guidance had converted the greatest part of the Irish people to Christianity. But the time was too short and the missionaries too few to instruct the newly-converted people fully in their faith: so that although they were Christians, many of them had only a poor knowledge of the Christian doctrine. In those times there were certain persons in Ireland called druids (for whom see pp. 136-138 above). They hated the Christian faith, and gave St. Patrick and his companions great trouble by trying to persuade the pagan Irish not to become Christians. They continued in the country till the time of St. Columkille, as active as ever though much fewer; and St. Columkille and the other missionaries of his time had often hard work to win over the people from the false teaching of these druids, and make good Christians of them.
 An exhaustive account of St. Columkille will be found in the Rev. William Reeves's edition of "Adamnan's Life of Saint Columba."
 In books he is often called Columba; but in Ireland he is best known by the name Columkille. This is derived from colum [pron. collum] a dove, and cill or kill, a church: the "Dove of the church." This name was given him when a boy from his gentle affectionate disposition, and because he was so fond of praying in the little church of Tullydouglas near where he was born: so that the little boys who were accustomed to play with him used often to ask: "Has our little Colum yet come from the church?"
The sketch given here is taken chiefly, but not altogether, from "Adamnan's Life of St. Columba." Adamnan was a native of Tirconnell or Donegal, like Columba himself. He died in the year 703. He was the ninth abbot of Iona of which Columba was the first. His "Life of St. Columba" is a very beautiful piece of Latin composition.