The Tagus port that Afonso Henriques and a crusader fleet took in 1147, seat of the Portuguese court from the thirteenth century, the city whose rising of 1383 made John of Aviz king, and the home port of Portugal's Atlantic voyages.
Lisbon rises on steep hills above the north shore of the Tagus, where the river widens into a sheltered inland sea, the Mar da Palha, before meeting the Atlantic. That anchorage made it the chief port of western Iberia under Roman, Muslim and Portuguese rule. Afonso Henriques took it from its Muslim rulers in 1147 with the help of a crusader fleet, and by the fourteenth century it was the seat of the Portuguese court, the kingdom's main market and the home of its richest merchants.
Lisbon's merchants and craftsmen backed John, Master of Aviz, in the crisis of 1383–1385 and held out against a Castilian blockade in 1384, putting a new dynasty on the throne. In the fifteenth century the city's shipyards, customs house and African trade paid for the voyages that ended, just after the period, with Vasco da Gama's return from India in 1499.
Roman Olisipo was a town of Lusitania, held after the fall of Roman rule by Sueves and then Visigoths. Muslim armies took it about 714, and as al-Ushbuna it became a walled port and district capital of al-Andalus. A Viking fleet attacked in 844, took much of the town and was driven off after about two weeks by the governor Wahb Allah ibn Hazm before sailing on to Seville.
Christian kings raided it more than once. Alfonso II of Asturias sacked it in the 790s, and in 1093 the king of Badajoz handed Lisbon, Santarém and Sintra to Alfonso VI of León in return for help against the Almoravids, who retook them within two years. When Almoravid power in al-Andalus broke up in the 1140s, Lisbon's leaders governed as a small independent power, sheltering refugees from Santarém, which Afonso Henriques had taken by surprise in March 1147.
In May 1147 a fleet of about 164 ships carrying crusaders from England, Normandy, Flanders and the Rhineland left Dartmouth for the Holy Land. Storms drove it into Porto, where Bishop Pedro Pitões persuaded its leaders to meet Afonso Henriques. The king promised them the plunder of the city and the ransom of its captives, and the Siege of Lisbon began at the start of July.
According to the crusader account, the English and Normans attacked from the west and the Germans and Flemings from the east. After seventeen weeks, with a siege tower against the wall and the town starving, the garrison agreed terms in late October. The Rhineland and Flemish contingents broke them, looting houses and killing the elderly Mozarab bishop. On 1 November the mosque was dedicated as the cathedral of Santa Maria, and Gilbert of Hastings, an English priest who had sailed with the fleet, became its bishop. The story of the knight Martim Moniz, who died wedging a castle gate open with his body, is a later legend.
Afonso Henriques gave the free Muslims who stayed a charter of their own in 1170, settling them in the Mouraria outside the walls, and granted the city its charter in 1179. In 1173 the relics of Saint Vincent were brought by sea from the cape in the Algarve that bears his name; by tradition ravens guarded the ship, and a ship with two ravens became the emblem of the city.
Afonso III, who completed the conquest of the Algarve in 1249, made Lisbon the usual seat of his court from about 1255. His son Denis founded a university there in 1290 and in 1317 hired the Genoese Manuel Pessanha as hereditary admiral, laying the basis of the royal fleet. The university moved between Lisbon and Coimbra several times before settling at Coimbra in 1537.
An earthquake in 1344 damaged the cathedral and the Black Death arrived in 1348. In 1373, during Ferdinand I of Portugal's wars with Castile, Henry II of Castile burned much of the lower town, and Ferdinand answered with a new and much longer wall, finished in about two years, which took in the riverside quarters.
Ferdinand died in October 1383 leaving only a daughter, Beatrice, married to John I of Castile. The regency of his widow, Leonor Teles, and her favourite, the Galician count João Fernandes Andeiro, was hated in Lisbon. On 6 December 1383 Ferdinand's half-brother John, Master of the Order of Aviz, killed Andeiro in the royal palace. Crowds rose in the streets, threw the bishop, suspected of siding with Castile, from a cathedral tower, and proclaimed John regent and defender of the realm.
John I of Castile blockaded Lisbon by land and river from May 1384. The city starved through the summer until plague broke out in the Castilian camp and forced the king to withdraw in September. The Cortes of Coimbra acclaimed the Master as John I in April 1385, and in August his army, led by the constable Nuno Álvares Pereira, won the Battle of Aljubarrota. Fernão Lopes, keeper of the royal archive in the Torre do Tombo from 1418, later wrote the classic account of the city's hunger and endurance.
Four kings made medieval Lisbon: Afonso Henriques won it, Afonso III brought the court there, Denis gave it a university and an admiral, and John I owed his crown to its citizens. Fernando Martins, born in the city about 1195, joined the Franciscans in 1220 after seeing the relics of five friars killed in Marrakesh, and died at Padua in 1231 as Saint Anthony. Pedro Julião, a physician usually identified with the logician Peter of Spain, became Pope John XXI in 1276, the only Portuguese pope.
Nuno Álvares Pereira, the victor of Aljubarrota, founded the Carmo convent above the Rossio in 1389 and died there as a lay brother in 1431. Isaac Abravanel, born in Lisbon in 1437, served Afonso V as a financier before fleeing to Castile in 1483, when John II suspected him of a part in the conspiracy of the Duke of Braganza.