Treaty of Tagilde
The Treaty of Tagilde is a treaty signed on 10 July 1372 in Tagilde, a village in Portugal. It was signed by King Ferdinand I of Portugal and representatives of John of Gaunt, Duke of Lancaster, a claimant to the Crown of Castile and son of the English king, Edward III. This agreement is considered to have constituted the first legal foundation of the Anglo-Portuguese Alliance, which continues to exist.