If for Grieg the early 1870s were largely concerned with solo songs, the next few years were to be dominated by music for the stage; however, in the event it was not Bjornson who was to provide the longed-for opportunity, but Ibsen.

The friendship between Grieg and Bjornson was close, if not without its ups and downs, and the poet's admiration for the composer was expressed in a verse he wrote in 1899:

In spite of the number of Bjornson's poems he set, Grieg remained more excited by the prospect of collaborating with him on a music-drama. He had first considered Arnljot Gelline, the cycle of poems from which he had taken the text of Foran Sydens kloster (Before the Southern Convent), with its theme that through suffering, and if he finds something worth fighting and dying for, a proud man can be brought to service and sacrifice. This might well have suited Grieg's mixture of the romantic and the realistic. However, after discussion, they decided to use Bjornson's play Olav Trygvason, written in 1861 while the author was in Italy. The history of this collaboration is long and involved and may be followed through the correspondence, frequently fiery, between the two.

Bjornson sent Grieg the first three scenes on 10 July 1873; in the accompanying letter he promised that ‘the whole act will follow shortly’. He was expecting the work to be ready for production in the autumn and gave Grieg instructions for the sort of music he wanted: ‘[It] must have a devilish speed! That is no joke. … Now comes a hellish hullabaloo for the miracle, and then more miracle, wild possession, dance, delirium, whee!’ Grieg replied a week later that he liked the scenes very much and he told Bjornson that a friend, Rasmus Rolfsen, had a small summerhouse on his estate Elsero at Sandviken, Bergen, which he had lent the composer to work in.