a state secret and thus the citizens were generally unaware of the danger in their midst. On the morning of October 12, 1654, Cornelis Soetens, the keeper of the magazine, opened the store to check a sample of the powder. A huge explosion followed. The exact cause of the explosion is unknown, as Soetens was killed, but it could have been from a spark from the light he was carrying.

The blast leveled the central part of the city, left a deep crater, blew out glass in large radius (including the stained glass and roof of the Nieuwe Kerk),