For a brief period in the early 12th-century, they were united under Máel Máedóc Ua Morgair (Saint Malachy), who also became Archbishop of Armagh.
[1] On 29 July 1438, plans for a permanent union of the sees of Down and Connor were submitted to King Henry VI of England for his sanction.
[2] Exactly twelve months later, 29 July 1439, Pope Eugene IV issued a papal bull stating that Down and Connor were to be united on the death or resignation of either bishop.
In 1442, Bishop John Sely of Down was deprived of his see by Pope Eugene IV,[3][4] thereby effecting the union of the two dioceses.
However, due to strong opposition to the union in the diocese of Down, three more bishops of Down were appointed, two whilst Fossade was alive and one after his death.