The Annals of Ulster record that "Amlaíb son of Sitriuc king of the foreigners was held prisoner by Mathgamain ua Riacáin king of Brega" in 1029 and ransomed for "1,200 cows and six score Welsh horses and sixty ounces of gold…". He was presumably born after the death of his brother Olaf in 1013, unless one or other of these sons was illegitimate.
The Annals of Ulster record that "Amlaíb son of Sitriuc was killed by the Saxons on his way to Rome". The Annals of Tigernach record that “Olaf son of Sitric was killed by Englishmen as he was going to Rome” in 1034. 1
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Chronicon Scotorum 1029: "Amlaíb son of Sitric was captured by Mathgamain ua Riacáin, king of southern Brega, and left twelve hundred cows and six score Welsh horses and three score unga of gold and the sword of Carlus as ransom and a mark for the man that captured him."
Annals of the Loch Cé 1029: "Amhlaibh, son of Sitric, king of the Foreigners, was taken prisoner by Mathghamhain Ua Riagain, king of Bregha, until he Amhlaibh gave twelve hundred cows, and six score British horses, and three score ounces of gold, and the sword of Carlus, and the hostages of the Gaeidhel, both of Laighen and Leth-Chuinn; and three scores ounces of white silver, as his fetter ounce. / Amhlaib mac Sitrec, rí Gall, do erghabháil do Mathghamhain .H. Riagháin, rí Breagh, go b-fhargaibh dha ced dhég bo, & .ui. xx. eoch m-bretnach, & tri xx uinge do ór, & cloidhem Carlusa, & aitire Gaoidel edir Laighnib & Leth Cuinn, & tri fichit uincce d' airged ghil ina h-uinge gheimhlidhe."
Annals of Ulster 1029: "Amlaíb son of Sitriuc, king of the foreigners, was held prisoner by Mathgamain ua Riacáin, king of Brega, and as his ransom he gave up 1,200 cows and six score Welsh horses and sixty ounces of gold and the sword of Carlus and Irish pledges both of Laigin and Conn's Half, and sixty ounces of pure silver; and four score cows was the portion of the award and the bequest, with four pledges, to ua Riacáin himself for peace, and full compensation for the release of one of the three pledges. / Amhlaim m. Sitriuc, ri Gall, do erghabhail do Mathgamain H. Riagain, ri Bregh, co fargaibh da .c. dec bo & .ui. xx. ech m-Bretnach & tri .xx. unga do or & cloidim Carlusa & aitire Gaidel eter Laigniu & Leth Cuind, & tri .xx. unga do argut gil ina ungai geimlech, cona cethri fichid bo cuid focall & impidhe & cethri oeitire d'O Riagain fein fri sith, & lan-logh braghad in treas oeiteire."
Chronicon Scotorum 1034: "Amlaíb son of Sitric was killed by the Saxons on his way to Rome."
Amlaíb was also called Óláfr.