O'Mulloy (Ua Máel Muaid), Ailbe (Aulbin) (d. 1223), last medieval Irish bishop of the diocese of Ferns (from c.1186), is remembered for his feud with William Marshal I (qv), earl marshal of England and heir of Richard de Clare (qv). This centred on Marshal's alleged illegal appropriation of two ecclesiastical manors, seemingly near Templeshambo and Ferns in Wexford. O'Mulloy, infuriated by Marshal's actions, took his case to the fourth Lateran council in Rome during 1216. For his considerable and vigorous efforts, O'Mulloy obtained a letter from Pope Innocent III directing the archbishops of Tuam and Dublin to warn the earl to return the lands on pain of excommunication. However, Marshal refused to countenance their return and was duly excommunicated. According to Matthew Paris, O'Mulloy sought an audience with Henry III in London on Marshal's death (1219). The king received him kindly, promising to intercede on his behalf with Marshal's successors. In return he asked the irate bishop to go to Marshal's tomb and lift the sentence of excommunication. The story goes that when O'Mulloy arrived at the spot, he addressed the earl's effigy as if it was a living person and threatened to confirm the sentence if his lands were not returned. This angered the king and Marshal's sons. Despite the king's intervention the Marshal family, led by William Marshal II (qv), stubbornly refused to return the lands to the bishop. Their stance enraged O'Mulloy, who according to legend confirmed the excommunication of the elder Marshal and predicted the extinction of his male line. Amazingly, by 1245 all the five sons of William Marshal had died without issue, with dire consequences for the colony. For his part, O'Mulloy died in 1223, having never recovered his lost lands.
AFM, iii, 203; Orpen, Normans, iii, 28–32; NHI, ix, 311