Lofsöngur is a hymn by Matthías Jochumsson with music by Sveinbjörn Sveinbjörnsson, both composed for a national celebration on the occasion of the thousandth anniversary of the settlement of Iceland in 1874. The song and poem were premiered by a mixed choir at a festive service that began at 10:30 in the Reykjavík Cathedral on Sunday, August 2, 1874 as Lofsöngur í míningún Íslands túlány ara (A Hymn in Memory of Iceland a Thousand Years), and the King of Denmark (and thus the King of Iceland), Christian IX, was present at the ceremony.

In 1942, Cyril Jackson handed over various documents belonging to Matthías Jochumsson. Among them was his autograph of the Hymn of Praise. The autograph is in a notebook and is Matthías's own writing from 1904. The manuscript contains the hymn in both Icelandic and Danish.

In the years 1953–1954, Elenore Sveinbjörnsson, Sveinbjörn's widow, gave the Icelandic nation various manuscripts by the composer, including a fully transcribed sheet music manuscript of the hymn.

Matthías' manuscript and Sveinbjarn's notes are preserved in the manuscript collection of the National and University Library of Iceland.

Furthermore, the manuscripts of the Song of Praise are featured on the museum's website in August.