[1] As he entered his office on the day of Amalgaidh's death, his appointment could not have been made by popular election, but on some other principle accepted and recognized by the clergy and people.
Sir James Ware, who terms Dubhdalethe archbishop of Armagh, finds a difficulty in the fact of Forreidh having been also bishop during his time; however, the coarb of Armagh, or primate in modern language, was not necessarily a bishop, and in the case of Dubhdalethe there is even some doubt whether he was ordained at all.
In 1055, according to the Annals of Ulster, he made war on another ecclesiastic, the coarb of Finnian(the Abbot of Clonard), in the south-west of the county of Meath.
Ware, however, states that, according to the Psalter of Cashel, it was only twelve, "afford[ing] some room to suspect that Gilla Patrick MacDonald, who is expressly called archbishop of Armagh in the Annals of the Four Masters at 1052, ought to intervene between Amalgaidh and Dubhdalethe, which will pretty well square with the death of the latter in 1065 [1064]".
The coarbs of St. Finnian, St. Columba, and other famous saints succeeded according to certain rules in which kinship to the founder played an important part.
He considered him as contemporary with Mugron, Abbot of Iona (Hy) (died 980), and as he must therefore have been at least sixty-nine years old when he became primate, and may naturally be presumed to have compiled his Annals at an earlier period, he may have been actually the first to use it.