1371 A new Ordinance concerning the Administration of Justice regulates criminal procedure. John of Gaunt, duke of Lancaster, claims the throne in right of his wife, Constanza, daughter of Pedro the Cruel.
1372 Battle off La Rochelle. Henry wins a naval victory over the English.
1373 Lisbon besieged by Henry, and the king of Portugal forced to make peace.
1379 Juan I makes alliance with France.
1380 The Castilians sail up the Thames and destroy the English shipping. Ferdinand of Portugal offers John of Gaunt his alliance.
1381 The earl of Cambridge arrives in Portugal with a few followers, but after some fighting in Castile returns to England.
1382 Beatrice, heiress of Portugal, marries Juan of Castile, but on the death of her father Ferdinand, her uncle João I usurps the Portuguese throne
1385 and defeats Juan of Castile in a great battle at Aljubarrota, where the Castilians lose ten thousand men.
1386 John of Gaunt lands in Galicia, is proclaimed king at Santiago, and with the
1387 help of the king of Portugal takes several fortresses, but is driven to retreat by an outbreak of plague in his army. John of Gaunt resigns his claims in return for fiefs and money and the marriage of his daughter with Juan’s eldest son, who receives the title of prince of Asturias, now first assigned to the heir of Castile.