Hallgrímur Pétursson's (1614 - 1974) most notable work is Passion Hymns (or "The history of the pain and death of our Lord, Jesus Christ, with its special learning, reminding, and consoling articles, with prayers and praises, in psalms and songs with misc. notes, compiled and written in the year 1659"), a collection of fifty hymns to be sung, one each working day, during the seven weeks of Lent. Each hymn has a title denoting which part of the Passion of Christ it refers to, and a reference to a melody for it to be sung to.

Hallgrímskirkja, church in Reykjavík is named aftur Hallgrímur Pétursson. 

Read more about Hallgrímur Pétursson and his work here