On 16 July 1906 the Rembrandt hall of the Amsterdam Rijksmuseum was opened by His Royal Highness Prince Hendrik. For this festive occasion Diepenbrock composed the Hymne aan Rembrandt (Hymn to Rembrandt, RC 70), which was to be performed during the evening programme. In addition, he was asked to write a four-part setting of the Dutch national anthem Wilhelmus van Nassouwe to be sung as a welcome to the royal guest of honour.
A month earlier Diepenbrock delivered a simple harmonisation without any accidentals or chromaticism. On the back of the manuscript he wrote to the conductor Anton Averkamp:
I have tried to keep it as archaic as possible, without becoming rather too stiff and empty. Also, I would have the choir sing the authentic original lyrics (van Dietschen bloet, blijf ik tot in den doet etc).
He said about the notation of measure 11:
Metrically I think a 3/2 metre suits the melody better and is more fluent than twice 3/4. (BD V:789)
The newspaper the Nieuwe Rotterdamsche Courant of 17 June 1906 had a report on the opening:
An impressive moment was the performance of the old Wilhelmus to welcome the Prince and the Queen’s Mother, which was sung with warmth and conviction by Averkamp’s choir. (BD V:674)
Someone, maybe Averkamp, has written a short three-measure sketch in pencil on the back of the manuscript, which was most likely used as organ or piano intonation. Curiously, this fragment is notated in A major. So it is possible that the piece was sung a semitone lower than the key of Diepenbrock’s setting.