ABSTRACT
On 16 April 1581 the Courts of Tomar designated Philip II of Spain as Philip I of Portugal (r. 1581–1598). 1 This marked the beginning of the period known in historiography as the Iberian Union (1581–1640). The dynastic crisis arose in Portugal after the death of King Sebastian (r. 1557–1578) in the battle of Alzaquivir, which left the realm without an heir. The crisis was not solved during King Henry’s short reign (r. 1578–1580). 2 Diplomacy, bribery and an effective four-month invasion led by the Duke of Alba gave Philip control over mainland Portugal. 3 António (1531–1595), Prior de Crato, an illegitimate grandson of King Manuel I (r. 1469–1521) was designated King of Portugal on 19 July 1580. However, soon afterwards Alba defeated António’s military contingent in the Battle of Alcântara on 25 August 1580 in the vicinity of Lisbon. António resisted with his flotilla until the Azores defeat in 1583. In 1581, Philip, now King of Portugal, progressed toward Lisbon.
