The tower of the 'Dorpskerk' at Wassenaar, a church that has been close to me since childhood. My interests and activities in church music and church organs started there.

An Easter song from the 7th century on a melody of a hymn by Ambrosius. In the 'Liedboek voor de Kerken' at which creation I was closely involved I tried to restore the old melodies to their original form as much as possible.

The opening of the 'Golden Kanon' from John Damascene. This Easter song played an important role in my discovery of the rhythm of Byzantine hymns.

The 'Anastasis', the Easter icon of the Eastern Church, painted by me after Greek models. Christ is raising Adam from the Hades, the realm of the dead.

The choir organ made by Jan van Covelens in 1511 in the 'Grote Kerk' at Alkmaar. During my investigations into the Dutch organs from the renaissance and barock period I made the discovery that Jan van Covelens should be seen as the proper founder of Dutch organ building.

The so-called 'Weckmeisterische Temperatur', one of the most brilliant welltempered tuning methods from the barock era. In my diagrams the numbers indicate the deviation from pure fifths and thirds measured in one twelfth of a Pythagorean comma (close to one eleventh of a syntonic comma).