Juan de Jáuregui was killed trying to assassinate Prince William I of Orange. He was a Biscayan by his birth in Bilbao.
In 1582, he was in the service of a Spanish fur merchant, Gaspar de Añastro from Vitoria, who resided at Antwerp. De Añastro had lost three ships and was tempted by the supposed reward of 80,000 ducats and the habit of the Order of Santiago offered by Philip II of Spain for the assassination of William the Silent, prince of Orange, and being himself without courage to undertake the task, De Añastro persuaded his poor accounting assistant Jáuregui to attempt the murder for the sum of 2877 crowns. Jáuregui had been convinced not only that heaven would smile on his attempt, but that he would become invisible immediately afterwards, and thus escape easily.
On Sunday, March 18, 1582, as the prince came out of his dining-room, Jáuregui offered him a petition, and William had no sooner taken it into his hand than Jáuregui fired a pistol at his head. Although the pistol was badly designed and malfunctioned, one bullet pierced the neck below the right ear and passed out at the left jaw-bone, but William ultimately recovered.