Temple Douglas was an ancient monastic site which used to stand on the old road out of Letterkenny, the main route for travellers passing through the area.
Colmcille is said to have been baptised here as a Christian in 521 by his foster father Cruithneachán mac Ceallachán.
It was common practice for the sons of noble families to be fostered as children. Foster fathers were expected to teach their foster-sons riding, marksmanship, swimming and how to play board-games.
Colmcille’s biographer and successor as Abbot of Iona, Adomnán, wrote
"One night St Columba’s foster-father, a priest of admirable life, whose name was Cruithneachán, was returning to his house from church after the office, when he saw the whole house bathed in a bright light, and poised over the face of the sleeping child was a fiery ball of light. He began to tremble, and bowed his face to the ground for he recognised that the grace of the Holy Ghost was poured from heaven upon his foster-son, and he stood in awe."
Life of St Columba by Adomnán of Iona, Book III Story 2
Although the story of Colmcille being baptised here is often stated as fact, there is no documentary evidence for the link between Tulach Dubhglaise and the saint. Saints are often linked with specific sites, even though there is no particular evidence for the association. These sites often have ancient monuments on them which pre-date the life of the saint.
The church on this site is said to have been rebuilt in the 16th century by Manus O’Donnell on the site of an earlier church.
This site formed part of a medieval pilgrimage route linking the sites in the Gartan area which were associated with the early life of Colmcille.