Referring to the post dd. 19/01/2014, here is the other piece based on the plainsong Kyrie (Orbis Factor) from the 10th century. The melody is the same, the accompaniment is different. I wrote it to the memory of Jos Beijer, who studied organ with me at the Utrecht Conservatorium from 1988 - 1995.
In the summer of 2011, both my mother and Jos Beijer, who studied organ with me at Utrecht Conservatoire from 1998 till 1995, were slowly passing away. I dedicated a piece to each of them, based on Kyrie (Orbis factor), a well-known Gregorian chant from the 10th century. Here is the piece dedicated to my mother, played on the ancient Freytag organ in Noordwolde: