'Op 1 april verloor Alva zijn bril' - Den Briel wordplay

APR 01 1572

On 1 April 1572 the Watergeuzen (Sea Beggars) captured Den Briel, a turning point in the Dutch Revolt against the Duke of Alva, producing the enduring pun 'Op 1 april verloor Alva zijn bril' ('On 1 April Alva lost his spectacles'), punning on Briel/bril. Dutch sources stress this is a folk etymology, NOT the origin of April Fools' Day, which is attested earlier and across Europe.