The Anglo-Portuguese Treaty of 1373 was signed on 16 June 1373 between King Edward III of England and King Ferdinand and Queen Eleanor of Portugal. It established a treaty of "perpetual friendships, unions [and] alliances" between the two seafaring nations. It is the oldest continuous treaty in effect to this day. It was reinforced throughout history, including in 1386, 1643, 1654, 1660, 1661, 1703, 1815, and by a secret declaration in 1899. It was recognized in the Treaties of Arbitration in the 20th century between Britain and Portugal in 1904 and 1914.