When was the anthem that Philips of Marnix likely wrote recognized as official?
Philips of Marnix, Lord of Saint-Aldegonde: Philips of Marnix, Lord of Saint-Aldegonde, Lord of West-Souburg (Dutch: Filips van Marnix, heer van Sint-Aldegonde, heer van West-Souburg, French: Philippe de Marnix, seigneur de Sainte-Aldegonde; Brussels, 7 March/20 July 1540 – Leiden, 15 December 1598) was a Flemish and Dutch writer and statesman, and the probable author of the text of the Dutch national anthem, the "Wilhelmus". Wilhelmus:  Although the "Wilhelmus" was not recognised as the official national anthem until 1932, it has always been popular with parts of the Dutch population and resurfaced on several occasions in the course of Dutch history before gaining its present status.
1932