Which medieval Icelandic author recorded a major prose account of Ragnarök?

Snorri Sturluson recorded a major prose account of Ragnarök in his 13th-century Edda.

Snorri was an Icelandic poet, historian, and law speaker who lived from about 1179 to 1241. His Prose Edda preserves explanations of Norse mythology and poetic technique, including the narrative of Ragnarök in the section called Gylfaginning.

Snorri’s account describes the Fimbulwinter, the gods’ final battles, the burning and submergence of the world, and the renewal that follows. His work is one of the most important surviving sources for interpreting Norse myth, although it was written after Iceland’s conversion to Christianity.

Snorri did not compose the older mythological poems of the Poetic Edda. Those poems survive in a separate manuscript tradition, especially the Codex Regius. Because Snorri often explains or arranges traditional material, researchers compare his prose with the poems when studying Ragnarök.