Karg-Elert’s Op. 65, the 66 chorale improvisations on Evangelical church hymns in six volumes, are his first organ works composed directly for this instrument. At first, in 1906, Karg-Elert had planned a collection of 40 preludes. In November 1909, the Opus 65, with its volumes arranged for the most part according to the liturgical year, was complete and in print, crowned with a piece for organ and brass as 66th setting.