Aedh became king after his father's death in 1265. He continued to
raid settled lands in his kingdom. In 1269 Robert d'Ufford, the new
justiciar in Ireland, began building a royal castle in
Roscommon. D'Ufford sent his deputy across the
River Shannon to join his ally,
Walter de Burgh, 1st Earl of Ulster. The combined forces met with Aedh to negotiate but to no avail. The forces under de Burgh retreated and attempted to ford the Shannon at Áth-an-Chip. Aedh routed the army and destroyed the castle at Roscommon. The battle occurred at Maigh Nissi (Moynissy, "plain of Nissi"), in the barony of Leitrim, County Leitrim. Connellan states "". Moynissy was the Gaelic place name for the flat, unforested part, of the
barony of Leitrim, bordering the
Shannon. The
Irish Annals describe the
Anglo-Normans crossing
Ath-Cara-Conaill ("Carrick-on-Shannon") before marching onward to Ath-an-cip. Places corrupted as "Ath an Chip" and all variants were a ford marked by a large tree stump. Ath an Chip was clearly a ford on the River Shannon. MacNamee states "". At
Leitrim village the
R284 road crosses the Shannon at "Battle-bridge" (, "the ford/mouth of the battle"). The townland at this bridge is Drumhierney (, meaning the ridge of the "master", "lord", or "the domination"). Without certainty the battle-site was Drumhierney townland in
county Leitrim. ==Aftermath==