In 1018, Sigtrygg plundered Kells; he "carried off innumerable spoils and prisoners, and slew many persons in the middle of the church". These captives would either have been ransomed or sold off into Dublin's lucrative slave trade. When Sigtrygg raided south in 1021, he was defeated at Delgany in County Wicklow where the new King of Leinster, Augaire mac Dúnlainge, "made a dreadful slaughter of the foreigners" in the Kingdom of Breifne. In 1022, the Dublin fleet sailed north against the Ulaid, only to be destroyed in a naval battle against Niall mac Eochaid, after which the Norse crews and ships were taken prisoner.