Ciarán Ó Cearbhalláin (825-10 March 868) was an Irish Catholic priest during the late 9th century AD. In 868, he and a band of clerics and women travelled across Ireland with the goal of spreading Christianity across the island, but the party was beset by Bjorn Tall-Trunks' Vikings in County Dublin. The priests pleaded poverty, but Bjorn instead massacred all of the priests and women and took their valuables.