In 1704 Árni Magnússon wrote to his friend in Norway, Þormóður Torfæus, that he had found in Iceland two fragments of a Latin Hungurvaka, in addition to the two he already had in Copenhagen (“2 blöd ur latinskre Hungurvöku gamalli hefi eg ödlast, og tvö á eg i Kaupenhafn”). Today the leaves are only three and they are preserved at The Árni Magnússon Institute in Reykjavík (AM 386 I 4to). The Latin text of the fragments is closely related to the vernacular works we know as Hungrvaka, the lives of the first five bishops of the episcopal see of Skálholt, and Þorláks saga, the life of the sixth bishop who was canonized in 1198. In their seventeenth-century transmission, these sagas are preserved combined, the latter following the former, which in turn serves as a sort of introduction to it. As Árni Magnússon already noted, the first fragment leaf marks the transition between books (libri), with a division in contents corresponding exactly to the vernacular texts: Liber primus treated the history of Skálholt through a series of episcopal lives, liber secundus presented the text of a Vita S. Thorlaci with a narrative of the translatio and miracula, of which there are remains in the two other leaves. The Latin fragments are considerably older (c. 1200) than any remains of the vernacular texts, and recent research has shown the text of Þorláks saga to be a vernacular redaction of the Latin Vita. This paper will present further evidence to argue that the said fragments derive from the combined text of *Gesta Scalotensis ecclesie presulum (c. 1193) by Lawspeaker Gizzur Hallsson († 1206) and the Vita S. Thorlaci (c. 1199) by Gunnlaugr Leifsson (†1218/19), a Benedictine of Þingeyrar Abbey, while the first redactor of the vernacular sagas was likely Gizzur’s son, Magnús, who was bishop of Skálholt from 1216-1237, as is indeed suggested in the first printed edition of Hungrvaka (1778).