Columba
Saint Columba (7 December 521 – 9 June 597 AD)—also known as Colum Cille, or Chille (Old Irish, meaning "dove of the church"), Colm Cille (Irish), Calum Cille (Scottish Gaelic), Colum Keeilley (Manx Gaelic) and Kolban or Kolbjørn (Old Norse)—was a Gaelic Irish missionary monk who propagated Christianity among the Picts during the Early Medieval Period. He was one of the Twelve Apostles of Ireland.
Read more about Columba: Early Life in Ireland, Scotland, Vita Columbae, Other Early Sources of Columba's Life