His most famous exploit was leading the
cavalry charge that won the
First Battle of Athenry in 1249. The Annals of Connacht relate that: The kings' sons of Connacht made another hosting, to burn and pillage
Athenry, at the feast of
Mary in mid-autumn. They went thither, a great host, including Toirrdelbach son of Aed and Aed son of Aed, and the Sheriff of Connacht was there to meet them, with many Galls. The Galls asked for a
truce on that day, on account of its sanctity; in honour of Mary Mother whose day it was. The princes would not grant that truce to honour Mary or the
Crucifixion, but attacked the town, though Toirrdelbach was unwilling. When Jordan [D'Exeter] and the Galls saw this they issued from the town against the princes. Mary wrought a miracle then; for when the princes and their followers saw the horsemen in arms and armour making towards them, horror and dread seized them and they were put to flight. Aed son of Aed O Conchobair was killed there, and Diarmait Ruad son of Cormac O Mailsechlainn, O Cellaig's two sons, Brian of the Wood son of Magnus, Carrach Insiubail son of Niall O Conchobair, Baethgalach Mac Aedacain, Mathgamain son of Tadc son of Diarmait Bachlach O Conchobair, Lochlainn O Conchobair's two sons, Domnall son of Cormac Mac Diarmata, Findanach Mac Branain, Cu Muman Mac Casurlaig and many others." Jordan himself was killed in 1258 while fending off a raid by
Dubhghall mac Ruaidhrí: A great fleet came from the
Hebrides with Mac Somurli. They sailed round the west of Ireland into
Connemara and robbed a merchant ship of all her goods; wine, copper, cloth and iron. The Sheriff of Connacht, Jordan d'Exeter, put out with a fleet full of Galls in pursuit of Mac Somurli and the fleet which had committed that piracy. Mac Somurli had landed on an island and drawn his ships up onto the land, and when they saw the Sheriff's fleet approaching he and his men put on their armour and fighting accoutrement. When the Sheriff reached the island he and his men, with those of the Galls who were ready with him, went quickly ashore. But he was met and dealt with by Mac Somurli and his men, being killed at once, together with Piers Accabard, an excellent knight of his company, and other good men. The fleet of the Galls retired after losing the best of their lords, and Mac Somurli went back to his land, joyful and laden with spoil. ==Family and descendants==