Even then Conchobar had to deal with the opposition of Áed's cousin, Murchad mac Máele Dúin. The latter was able to form an alliance with one of Conchobar's own subject kindreds, the Síl nÁedo Sláine. Conchobar soon became aware of the treachery, and in 822 he took revenge on this kindred in "an especially horrific slaughter".Hudson, "Conchobar mac Donnchada (d. 833)". In 823 Conchobar formed an alliance with Feidlimid mac Crimthainn, King of Munster (820–847). However, Conchobar's attempts to subordinate Munster and its king proved intolerable to Feidlimid, and from 827 onwards Feidlimid mac Crimthainn was a source of opposition.Hudson, "Conchobar mac Donnchada (d. 833)"; Moody, Martin, and Byrne, (eds.), Maps, Genealogies, Lists, p. 193, n. 26.
