Willem Bloys van Treslong

Willem Bloys van Treslong (1529 – 17 July 1594) was a nobleman from the Southern Netherlands and military leader during the Dutch war of Independence.

In 1571, William the Silent provided him with letters of marque and equipped two ships to join the Sea Beggars.

In March 1572, Bloys van Treslong's ships were trapped by ice at Wieringen and were attacked by four Spanish companies of infantry.

Bloys escaped from the Spaniards, but lost his sword which at present hangs in the Michaëlskerk church in Oosterland.

After a dispute over the strategy for the relief of Antwerp in 1585, he fell out of favour and ended up in jail, believed to have been under the custody of Count Steijn.