Otto Olsson held the post of organist at Gustaf Vasa Church in Stockholm for nigh on 50 years, from 1907 to 1956. He also taught harmony and organ at the Stockholm Conservatory of Music from 1908 to 1945, but to his contemporaries he was best known as a choral composer and writer of organ music. Advent, for choir and organ, is sung in most Swedish churches on the first Sunday in Advent, and his organ pieces are played by virtually every organist in Sweden with sufficient command of the instrument. Otto Olsson wrote Requiem at the age of 23. The reason why he wrote this piece is unclear, but perhaps it was intended as a tribute to his father who died in November, 1900. He could very well have been inspired by the Requiems of Brahms and Verdi which were performed in Stockholm in April, 1900 and December, 1901, just when he had started on his own Requiem (the score is dated 1901–03).