Mac Cerbaill (MacCarwell), David (d. 1289), archbishop of Cashel, was most probably born in Co. Tipperary into an important native Irish ecclesiastical family, for, in a petition dated 1274 asking for the grant of certain privileges to the abbeys of Jerpoint and Cashel, he states that Jerpoint had been founded by his ancestors. He was dean of Cashel in 1253, the year in which his predecessor as archbishop of Cashel, David MacGillapatrick (qv), died. Mac Cearbaill received his appointment as archbishop in the following year, but did not obtain the royal assent to it until 19 February 1255 because of his kinship and ties of friendship with men who had plotted against the crown. He did fealty before Henry III at Winchester in the following April, during the first of many lengthy visits to England that he made during his long career. In 1255 he asked to have two Cistercian monks from the Irish community appointed as his assistants. From the start he showed himself to be an independent and strong-minded prelate. In 1266 he consecrated the bishop of Kilfenora without waiting for royal assent and confirmed the election of the bishop of Emly. He received royal grace for these transgressions the following year, having fully acknowledged the king's rights in this matter.
In 1269 he became a Cistercian monk. He was zealous in his enforcement of discipline in the Cistercian houses within his archdiocese and on its borders, to judge by the censures raised against some Irish houses at a succession of chapters general of the Cistercian order held at Cîteaux between 1270 and 1274. In July 1274 he attended the final session of the ecumenical council of Lyons, called by Gregory X, which the abbot of Cîteaux, the head of the Cistercian order, also attended. In September of that year, David himself attended the Cistercian chapter general, where he gained accession to two requests – that the arrangements made in 1228 by Stephen of Lexington, whereby the twenty-four daughter houses of Mellifont (the so-called filiatio Mellifontis) were placed under the control of English houses, be reversed, and that the feast of St Patrick be observed in all Irish Cistercian houses. His foundation of Hore Abbey, near the Rock of Cashel, also received approval. No doubt all of these matters had been negotiated between David and the head of the Cistercian order at Lyons in the previous July. From then on he adopted a policy of appointing Cistercians to the suffragan bishoprics of his archdiocese, so that by 1277, four of the ten suffragan bishops of the archdiocese were Cistercians, chosen by him.
There is evidence from 1277 that he had collected a large sum of money for the ‘purchase of French law [English common law] for the Irish', perhaps as part of his attempted reconciliation with Edward I, who had previously granted to the archbishop and his successors free possession of the newly constructed gaol in the city of Cashel, over which the archbishop had been in fierce dispute with the king's council in Ireland. The archbishop seems to have wished to cement his relationship with the king by offering a substantial sum of money for the purchase of English law, ‘to put an end to the evil law and the disaffection which is in the land of Ireland concerning the Irish tongue'. The effect of this would have been to strengthen the allegiance of the Irish to the crown and increase the input of the clerical estate into royal government in Ireland. The initial sum offered of 7,000 marks was eventually increased to 10,000. During these negotiations Mac Cearbaill was resident in England, where in 1280 he was joined by the bishops of Killaloe and Emly, his suffragans, and by the abbot of Holy Cross. They had previously attended a council of bishops and senior clergy in Ireland to debate the legal technicalities of the king's proposed offer of English law, and had apparently returned to England to report back to him. Archbishop David remained in England for the following three years: the Annals of Inisfallen report his return to Ireland in 1283. Similar rights of access to English common law had been granted to some kinsmen and friends of the archbishop before 1272. But the intended general purchase of English common law for most of the Irish nation never materialised, not only because the people and clergy of Ulster were excluded from the proposed grant, but because the senior clergy outside the archbishop's own ecclesiastical province were apparently not asked for their support. In any case it is likely that the king had personal reservations about the advisability of such a grant.
Notwithstanding its ultimate failure, this grand scheme shows the character of Archbishop David as an extremely ambitious, not to say power-hungry, prelate. His episcopacy ended as it had begun, in dispute with his fellow bishops and the escheator who had several claims against him. He died 1289, on or before the feast of St Peter's Chains (1 August), from which date the crown escheated the temporalities of his archdiocese. He was buried at Hore Abbey.