 His troops got lost in a dense fog and were discovered by the postal courier on Hamburg, who also warned Andries' son Gerard, the high bailiff of Muiden, to leave without delay for Amsterdam.The mayors of Amsterdam had the civic guard called out, the bridges raised, the gates closed and the artillery dragged into position.Andries Bicker was purged from the vroedschap, as was his brother Cornelis, as one of the conditions of the treaty that followed, led by Joan Huydecoper van Maarsseveen.