The parish of Kilbannon owes its name to St. Benen, or Benignus, signifying the Church of Benen. He was the son of Sescan, a chief who dwelt near the modern Duleek in Meath. He was but a boy when St. Patrick visited his native district and he was so attracted to the great Apostle that he watched his every movement, followed him around, gathered flowers as an offering to him, and when St. Patrick was leaving the district he insisted on going with him. And St. Patrick returned his affection, appointed him later one of the commissioners to codify the Brehon Laws, and brought him with him on his missionary journeys. Thus it happened that Benen, or Benignus, was with St. Patrick when he visited the Conmaicne of Chineal Dublain, the Conmaicne of the Dunmore District, and when a suitable site for a church was obtained at Kilbannon, St. Patrick appointed Benen as head of the church and head of a school for the training of priests. It was there that St. Jarlath and St. Conla were trained. Benen then a priest, subsequently became Coadjutor to St. Patrick in the See of Armagh. He was author of the "Psalter of Cashel", and probably also the "Book of Rights", thought not in its present form; and for a time he was head of the college established at Armagh. He died at Armagh in 468.

The church of Benen was the mother church of the Archdiocese of Tuam, older than Tuam itself, as Benignus was older the St. Jarlath. And it importance was attested by the fact that a round tower was erected there about 1000 A.D., for the round tower usually marked the residence of an important chief or king, and served to guard the church that was built in its shadows. Nor is it unlikely that Kilbannon would have become the seat of the Archbishop if the O'Connor kings had not made Tuam their chief residence in the eleventh century. This was done by Aedh O'Connor who defeated O'Flaherty in 1047, and who then selected Tuam as a convenient place for attacking these powerful O'Flaherty chiefs. The churches of the Conmaicne of Dunmore were in these days subject to Kilbannon, just as those of Conmaicne Mara and Conmaicne of Cuil Talach were subject to the Abbot of Cong. In the time of Turlough O'Conner Tuam had risen to such prominence that it was made the See of the Archbishop as soon as diocesan episcopacy supplanted finally the old monastic system. Then Kilbannon ceased to be the ruling church, and when the Chapter was formed, the tithes of Kilbannon formed part of the revenue of the Chapter. But as a Patrician church its revenues were claimed by the Archbishop of Armagh, and in 1216 , when the Archbishop of Tuam was sending his complaints to Rome, he complained that the Primate had despoiled him of the Church of Kilbannon. The dispute dragged on. At 1243 it is recorded that Finuachta O'Lugadha, Comhrab of Benen, and great dean of Tuam died; and when the final settlement was arrived at between Tuam and Armagh in 1351, among the places definitely attached to Tuam was Kilbannon.

The connection with Kilconly is not clear, it is known that St. Conla was educated in Kilbannon and when he left he traveled about five miles west and founded his own church. In the earlier centuries, Kilbannon was always the more important church; but in the taxation of 1306 Kilbannon and Kilconly were put together as belonging to the Dean and Chapter of Tuam. Subsequently the two parishes were permanently united and in the return furnished to the Government in 1800 by Dr. Dillon, the Archbishop of Tuam.