Kristni saga is an Old Norse account of the Christianization of Iceland in the 10th century and of some later church history. It was probably written in the early or mid-13th century, as it is dependent on the Latin biography of King Olaf Tryggvason written by the monk Gunnlaugr Leifsson around the last decade of the 12th century. This results in Latinate forms of some names. The author also used work by Ari Þorgilsson, probably the now lost longer version of the Íslendingabók, and Laxdæla saga. Based on the region of Iceland with which the text indicates the greatest familiarity, it was probably not written at Skálholt.