Ólafs ríma Haraldssonar is a 14th century ríma

Rímur

In Icelandic literature, a ríma is an epic poem written in any of the so-called rímnahættir . They are rhymed, they alliterate and consist of two to four lines per stanza...

by Einarr Gilsson

Einarr Gilsson

Einarr Gilsson was an Icelandic poet and official. He was the lögmaður of northern and western Iceland from 1367 to 1369. He is mentioned already in letters dating from 1339 and 1340 but his years of birth and death are unknown...

 on the career of Saint Óláfr Haraldsson of Norway.

The work is preserved in Flateyjarbók

Flateyjarbók

The Flatey Book, is an important medieval Icelandic manuscript. It is also known as GkS 1005 fol. and by the Latin name Codex Flateyensis.- Description :...

, from around 1390, and was probably composed a couple of decades earlier. The narrative follows the account of Óláfr's life in Heimskringla

Heimskringla

Heimskringla is the best known of the Old Norse kings' sagas. It was written in Old Norse in Iceland by the poet and historian Snorri Sturluson ca. 1230...

, focusing on the Battle of Stiklestad

Battle of Stiklestad

The Battle of Stiklestad in 1030 is one of the most famous battles in the history of Norway. In this battle, King Olaf II of Norway was killed. He was later canonized...

 and Óláfr's miracles after his death. The work is literary though the diction is simple. The ríma consists of 65 ferskeytt verses. There is no mansöngr

Mansöngr

A Mansöngr is a form of erotic poetry in Iceland, both in medieval skaldic poetry and in modern rímur.In the Ljóðatal section of the Hávamál, charms 16 and 17 are explicitly love charms....

.

Ólafs ríma is often considered the earliest ríma.