On 1 April 1572 – the day of the Capture of Brielle – the Sea Beggars were led by De la Marck, and by two of his captains, Willem Bloys van Treslong and Lenaert Jansz de Graeff. After they were expelled from England by Elizabeth I, they needed a place to shelter their 25 ships. As they sailed towards Brill, they were surprised to find out that the Spanish garrison had left in order to deal with trouble in Utrecht. On the evening of 1 April, the 600 men sacked the undefended port.