On Easter day, a contingent of about 600 longbow men, veterans of the Hundred Years’ War battles, and well schooled in efficient English military tactics, arrived to help Portugal in its war against the Castilians. This started the oldest diplomatic alliance in the world, which is still in effect today.
On April 6, 1385, John (João), the Grand Master of the Aviz Order was proclaimed John I of Portugal in defiance of Juan of Castile who tried to be recognized as monarch iure uxoris, against the Treaty of Salvaterra.