 Separately from Sláine , Sigtrygg had five children : <unk> ( d . 999 ) , Oleif ( d . 1013 ) , Godfrey ( d . 1036 ) , Glúniairn ( d . 1031 ) and Cellach ( d . 1042 ) . The annals record the death of Oleif — " son of the lord of the foreigners " — who was killed in revenge for the burning of Cork . Glúniairn was killed by the people of South Brega in 1031 . Godfrey was killed in Wales in 1036 by one Sitric , " son of Glúniairn " — as factionalism was common among Viking settlers , this could have been the same Glúniairn as Sigtrygg 's half @-@ brother , thus making Godfrey and his killer cousins . Sigtrygg 's daughter Cellach died in the same month as her father . 
