 Modern historians do not assume that these late sources are accurate, and their credibility is debated.The most detailed account is named "Óláfs saga Tryggvasonar en mesta" ("Greatest Saga of Óláfr Tryggvason") and is recorded in the "Flateyjarbók", and in the early 15th-century "Bergsbók".The account in this article is primarily based on the late sagas.