The Siege of Santarém, lasted from June 1184 to July 1184. In the spring of 1184, Abu Yaqub Yusuf

Abu Yaqub Yusuf

Abu Ya`qub Yusuf or Yusuf I was the second Almohad Amir or caliph. He reigned from 1163 until 1184. He had the Giralda in Seville built....

 assembled an army, crossed the straits of Gibraltar and marched to Seville. From there he marched towards Badajoz and headed west to besiege Santarém, which was defended by Afonso I of Portugal

Afonso I of Portugal

Afonso I or Dom Afonso Henriques , more commonly known as Afonso Henriques , nicknamed "the Conqueror" , "the Founder" or "the Great" by the Portuguese, and El-Bortukali and Ibn-Arrik by the Moors whom he fought, was the first King of Portugal...

. Upon hearing of Abu Yusuf's attack, Ferdinand II of León

Ferdinand II of Leon

Ferdinand II was King of León and Galicia from 1157 to his death.-Life:Born in Toledo, Castile, he was the son of King Alfonso VII of León and Castile and of Berenguela, of the House of Barcelona. At his father's death, he received León and Galicia, while his brother Sancho received Castile and...

 marched his troops to Santarém to support his father in law, Afonso I.

Death of Yusuf

Abu Yusuf, believing he had sufficient troops to maintain the siege, sent orders for part of his army to march to Lisbon

Lisbon

Lisbon is the capital city and largest city of Portugal with a population of 545,245 within its administrative limits on a land area of . The urban area of Lisbon extends beyond the administrative city limits with a population of 3 million on an area of , making it the 9th most populous urban...

and lay siege to that city. The orders were misinterpreted and his army, seeing large contingents of men leaving the battle, became confused and started to retreat. Abu Yusuf, in an attempt to rally his troops, was wounded by a crossbow bolt and died on July 29, 1184.

Papal Recognition

The victory at Santarém was a major achievement for Afonso I. Pope Alexander III formally recognized him as rex Portugalensium.