Fóstbrœðra saga ( listen ) or The Saga of the Sworn Brothers is one of the Icelanders' sagas. It relates the deeds of the sworn brothers Þorgeirr and Þormóðr in early 11th century Iceland and abroad. Þorgeirr is a capable and insanely brave warrior. He kills people for trifles and for sport. Þormóðr is a more complicated character; warrior, trouble-maker, womanizer and poet. The saga contains poetry attributed to him, including parts of a lay on his blood brother.
The saga survives in three early manuscripts. Each has a rather different version of the text:
The date of composition of the lost written archetype of Fóstbrœðra saga has been the subject of considerable dispute. Sigurður Nordal argued for ca. 1200 (Björn K. Þorólfsson and Guðni Jónsson 1943: lxxii) whereas Jónas Kristjánsson argued for the end of the century (1972, 310). There is no clear consensus, though Andersson's 2013 analysis preferred an early dating of 'presumably not much later than 1200' (2013, 72).
A long-standing controversy centers on which manuscripts represent the most original version. In particular, the debate has focused on several unusual "clauses" (Icelandic klausur) or asides in the saga which do not fit in with conventional saga style. These have been understood both as late interpolations and as signs of an early, developing saga style (Jónas Kristjánsson 1972).
The skaldic stanzas attributed to Þormóðr kolbrúnarskáld Bersason appear genuine (according to Guðni Jónsson in Björn K. Þorólfsson and Guðni Jónsson 1943: lxi); he would have composed ca. 1010-1030 (according to Guðni Jónsson in Björn K. Þorólfsson and Guðni Jónsson 1943: lxix).