> The complete text comprises fifteen stanzas. The anthem is an acrostic: the first letters of the fifteen stanzas formed the name "Willem van Nassov" (Nassov was a contemporary orthographic variant of Nassau). In the current Dutch spelling the first words of the 12th and 13th stanzas begin with Z instead of S. [0]
[0] https://en.wikipedia.org/wiki/Wilhelmus#Structure_and_interp...