De expugnatione Lyxbonensi is an eyewitness account of the Siege of Lisbon. It covers the expedition from the departure of the English contingent until the fall of Lisbon. “The first groups to depart on the Second Crusade were Anglo-Norman and Flemish sailors and troops who left Dartmouth on May 19, 1147 bound for Spain. Their goal was to conquer a number of position on the west coast of Iberia, among them the city of Lisbon. Afonso I of Portugal was already in the field there when the Anglo-Norman troops landed on the beaches in June 1147.”
According to the legend, a knight called Martim Moniz participated in the Christian invasion force, led by king Afonso I of Portugal. During the siege of the Castle, he saw the Moors closing the castle doors. He led an attack on the doors, and sacrificed himself by lodging himself in the doorway. Consequently, he prevented the defenders from fully closing the door.
The Siege of Lisbon was one of the few Christian victories of the 2nd Crusade.
The conquest of Lisbon ends 437 years of Moorish occupation. Lisbon was taken by Muslim forces on 6 August 711.