Descendants of Céileacháin mac Garbhith mac Aedh, who d. 933 and was pregenitor of the Ó Céileacháin, an Airgialla family who were lords of the Ui Breasaill Airthir and abbots of the Church of Armagh; The given name is either a diminutive of céile: companion; vassal, or céileach: wise; prudent; The surname developed a "Mac" alias in Monaghan and was numerous on the borders of Cavan & Meath; A branch of this family settled near Athboy, Co. Meath who were displaced during the Norman invasion. Anglicized Keelaghan, Keleghan, Kilaghan, Keelan, Kellan, Keelane, Clane, McKeelan, McKelane, McClean. Many variants are confused with a half-dozen other surnames. --------- Annalistic References to this family in 10th-11th century Armagh: 933. Céilecán son of Gairbíth, chief of Int Airthir, died. 986. A great disturbance in Ard Macha on the Sunday 25 July before Lammas between the Uí Echach and the Uí Nialláin, and in it the son of Trénar son of Celecán and others fell. 1002. Tréinfher son of Céilecán, prior of Ard Macha, was killed by Mac Léiginn son of Cairell, king of Fernmag. 1021. Aed ua Néill's son brought a raiding party over the Uí Dorthain who were in Mag Itechta, and they slew in Lethderg in the pursuit. And the best part of the Airgialla caught up with him from behind and came in front of him, or the Uí Méith and the Mugdorna and the Saithne and the men of Fernmag and the Uí Dorthain with their kings overtook him. Ua Ceilecháin and ua Lorcáin with the Uí Bresail and the Uí Nialláin, moreover, were waiting for him in Ard Macha and they all surrounded him; and Aed's son took his spoils past them all, though he had only twelve score warriors. And a good number on both sides fell in the middle of Ard Macha. 1037. Árchú ua Ceilecáin, i.e. king of Uí Bresail, and Ruaidrí ua Lorcáin, king of Uí Nialláin, were killed in Craeb Chaille by Muiredach ua Ruadacáin and by the Uí Echach. 1038. Colman Cam ua Conghaile ri H.m-Bresail, slain by Matadan ua Ceilecan 1044. Niall ua Céilecáin, king of Uí Bresail, and his kinsman Tréinfher, were treacherously blinded by the sons of Matudán. 1047. Muirchertach, son of Madadhan, king of Uí-Bresail, was killed in Ard-Macha, by Madadhan Ua Celechain secundus abbatis of Armagh. 1052. Gilla Pátraic son of Domnall, prior of Ard Macha, was treacherously killed by the son of Árchú ua Céilecáin. 1054. The son of Archu Ua Celechain, king of Uí-Bresail, were slain by the men of Fernmhag. 1063. Motodán ua Celecáin, prior of Ard Macha, died. 1077. Ua Célecán, heir designate of Airthir, was killed. 1089. Gilla Pátraic ua Célecán, prior of Ard Macha, died on Christmas Eve. 1096. Cú Ulad ua Ceilecán, i.e. heir designate of Airgialla, was killed by the province of Ireland, i.e. by the Ulaid.