Brjáns saga (also Brjánssaga) is a hypothetical early specimen of Old Norse literature.
He believed it could have been written as early as the 1190s, and used by the author of Orkneyinga saga, who wrote in about 1200.
A controversial approach by the Irish academic Donnchadh Ó Corráin has attracted notice.
He believed that the likely date of composition of the original Brjáns saga was around 1100, when Magnus Barelegs posed a threat to Irish interests (Clarke et al., 1998, p. 449).
After that they traveled to Ireland and fought with king Brian, and there many remarkable events happened at the same time as is said in his Saga."