He was the last bishop of the united diocese of Sodor, which split into the "Scottish" and "Irish" (Manx) parts because of the Western Schism.
[3] This service in Ireland was further rewarded in 1374 when he was appointed Bishop of Man and the Isles (Sodor), receiving consecration from Simon Langham, Cardinal-Bishop of Palestrina on either 25 or 26 November 1374.
[6] In 1380, allegations were lodged against Dongan that revenues he had been collecting – in an official capacity as collector in Ireland for Pope Urban – were illegally retained.
[6] By this point the non-Avignon papacy, under Pope Boniface IX (Urban's successor), decided to move Dongan into an Irish see.
Ireland was (as a territory of the King of England) in their allegiance and thus candidates they appointed to Irish bishoprics could actually expect to take physical possession.
[11] As the bishop of Down, his most notable role was his diplomatic interactions on behalf of the English crown with the native Gaelic leaders of Ireland and Scotland.