Ólchobar was previously thought to have belonged to the Locha Léin branch of the Eóganachta, the kindred which dominated the kingship of Munster from the 6th to the late 10th centuries, whose lands lay around the Lakes of Killarney.
This branch, found in the east of modern County Limerick, was part of the inner circle of Eoganachta which had rotated the kingship of Munster since the 7th century.
[3] Some of the Irish annals, among them the Chronicon Scotorum, record that early in Ólchobar's reign Emly was attacked by a Viking force.
Early sources say two hundred Vikings were killed, later ones increase the number of dead, among them one Tomrair, jarl and deputy of the king of Laithlind.
For that reason, the king of the Irish sends ambassadors with gifts to Charles for the sake of peace and friendship and with the request to allow him free passage to Rome.