Codex Regius
Codex Regius (, "Royal Book" or "King's Book"; ) or GKS 2365 4º is an Icelandic codex in which many Old Norse poems are preserved. Thought to have been written during the 1270s, it is made up of 45 vellum leaves. The work originally contained a further eight leaves, which are now missing. It is the sole source for most of the poems it contains. In scholarly texts, this manuscript is commonly abbreviated as [R] for Codex Regius, or as [K] for Konungsbók.