For much of the information in this page I am extremely grateful to Mr John Caine who has made a special study of Onchan.
Manx tradition (16th C Ballad on Mannanan vv 19-20) speaks of Connaghyn as bishop in Mann after Ma Rooney. The latinised form of the name is Conchan which is first found in a 1414 Castle Rushen recording the donation of the Church of St Conchan to the Monestary of St Mary in Douglas.
Dempsey was of the opinion that he was identical with the Irish Saint Connaghyn.
Megaw points out that Kirk Conchan is a norse adaptation of a much earlier (pre 8th C) Celtic name probably of the form Cill Chonchain which may even date from the 5th C. His opinion is that the dedication to some obscure insular saint, the founder of the building, at whose site his tomb was venerated. Conchan was like the other Manx saints a common name in the region. Megaw also points out the strong British links in the 5-8 C when the welsh speaking British, stretching from Southern Scotland through to Cornwall, during the invasions of the pagan English maintained a strong sub-Roman culture with links to Gaul. It is thus possible that Conchan was of British descent.

B.R.S.Megaw Who was Saint Conchan Journal Manx Museum 6 pp187/92 1964

Namesake of Onchan Parish