Santarém, Siege of

After Abu Yusuf Yaqub al-Mansur, upon reaching Seville on August 10 with the body of his father, killed in Portugal on July 29, 1184, had immediately been proclaimed the new caliph.

Al-Mansur had vowed revenge for his father's death, but fighting with the Almoravids, who had been ousted from the throne, had delayed him in Africa.

After inflicting a new defeat on the Almoravids, he had set off for the Iberian Peninsula to avenge his father's death.

His siege of Tomar, center of the Portuguese Templars, on July 13, 1190, had failed to capture the fortress.

However, further south he in 1191 recaptures a major fortress, Paderne Castle and the surrounding territory near Albufeira, in the Algarve—which has been controlled by the Portuguese army of King Sancho I since 1182.

Having inflicted other defeats on the Christians and captured major cities, he returns to Morocco with three thousand Christian captives.

Abu Yaqub Yusuf assembles an army in the spring of 1184, crosses the straits of Gibraltar and marches to Seville.

From here, he marches towards Badajoz.

The Almohad Counteroffensive and the Siege of Lisbon (1184)

In 1184, launching an offensive from Badajoz,...

...they advanced toward Lisbon, laying siege to the city by land and deploying their naval fleet to blockade its port.

A Daring Act of Heroism

During the siege, a Portuguese soldier carried out a bold and decisive act, swimming to the Almohad fleet’s largest ship and successfully sinking it. This vessel, towering over the harbor, posed a serious threat to Lisbon’s defenses, as it would have allowed the besieging forces to easily scale the city walls.

The Almohad Retreat

With the loss of their most critical naval asset, the Almohads found themselves at a disadvantage. By the next day, they were forced to abandon the siege, though they withdrew with a number of Portuguese civilian captives taken during their retreat.

This failed siege marked an important moment in the ongoing struggle between Christian Portugal and Muslim Al-Andalus, reaffirming Lisbon’s strategic resilience and the growing strength of Afonso I’s kingdom.

The Siege of Santarém and the Death of Abu Yusuf (1184)

In 1184, upon hearing of Abu Yusuf Yaqub ibn Abd al-Mu’min’s invasion, Ferdinand II of León swiftly marched his forces to Santarém to aid his father-in-law, Afonso I of Portugal, in repelling the Almohad offensive. The Almohads, having already failed to capture Lisbon, now turned their focus on Santarém, a key stronghold in central Portugal.

Strategic Miscommunication and Almohad Retreat

Confident in his numerical superiority, Abu Yusuf ordered a portion of his army to advance toward Lisbon while maintaining the siege of Santarém. However, the orders were misinterpreted, leading to confusion among the Almohad ranks. As large contingents of men began withdrawing from the battlefield, the rest of the army mistook this for a general retreat and lost cohesion, prompting a disorderly withdrawal.

The Death of Abu Yusuf (July 29, 1184)

In a desperate attempt to rally his forces, Abu Yusuf personally took to the battlefield. Amid the chaos, he was struck by a crossbow bolt and fatally wounded, dying on July 29, 1184. His death marked a major blow to the Almohad campaign, forcing the Muslim forces to abandon the siege and retreat southward.

This victory further solidified Portuguese resilience against the Almohads and reinforced Santarém’s strategic importance in the kingdom’s defense.