The taifa of Murcia has passed successively under the rule of Almería, Toledo and Seville after the fall of the Caliphate of Cordoba in 1031.

Abbad II al-Mu'tadid brings the taifa kingdom under the forcible control of Seville from 1078.

Al-Mu'tamid ibn Abbad, who had inherited Seville after the death of his father Abbad II al-Mu'tadid in 1069, had attempted in 1071 to seize neighboring Córdoba and lost its in 1075; he regains it in 1078.

The Muslim ruler al-Mu'tamid of Sevilla, following the fall of Toledo to the Christians and Alfonso's subsequent oppression of Muslim vassals, takes a desperate decision and calls for the help of Yusuf ibn Tashufin, the Almoravid emir of North Africa, and his Saharan Berber tribesmen.

The emirs of the smaller taifa kingdoms of Islamic Iberia had found, after Alfonso VI captured Toledo in 1085 and invaded the taifa of Zaragoza, that they cannot resist against his possible conquest without external assistance.

Yusuf ibn Tashfin, Sultan of Morocco and leader of the ascetic Muslim Berbers known as the Almoravids, is invited by them, with some reluctance, to fight against Alfonso VI.

He replies in 1086 to the call of three Andalusian leaders (Al-Mu'tamid ibn Abbad and others) and crosses the straits to Algeciras, disembarking at the end of July.

Yusuf moves to Seville, and from here, accompanied by the emirs of Seville, Granada and the Taifa of Málaga, marches to Badajoz with a large combined army.

Alfonso VI abandons the siege of Zaragoza, recalls his troops from Valencia and appeals to Sancho I of Aragon for help.

Finally he sets out to confront the enemy northeast of Badajoz, where the two armies meet on October 23, 1086 at the Battle of the Sagrajas.

Alfonso reaches the battleground with some twenty-five hundred men, including fifteen hundred cavalry, in which seven hundred and fifty are knights, but finds himself outnumbered, reportedly three to one.

The two leaders exchange messages before the battle.

Yusuf is reputed to have offered three choices to the Castilians: convert to Islam, to pay tribute (jizyah), or battle.

French nobles arrive with reinforcements, but are too late to save the Castilian-Aragonese forces from a crushing defeat.

Many Jews reportedly fought together with Alfonso against the Almoravids.

The Moslem armies also had a large number of Jews serving in them, so much so that the battle had been arranged not to fall on the Sabbath.

While the numbers may be exaggerated, they reflect the fact that Jews actually took part in most of the Spanish wars of the period.

At least half the Castilian army is lost.

One lone source claims that only five hundred knights returned to Castile, although others do not support this low figure, so it seems that most of the nobility survived.

The dead include counts Rodrigo Muñoz and Vela Oveguez.

King Alfonso VI sustains an injury to one leg that will cause him to limp for the rest of his life.

Casualties are also heavy on the Almoravid side, especially for the hosts led by Dawud ibn Aysa, whose camp had been sacked in the first hours of battle, and by the emir of Badajoz, al-Mutawakkil ibn al-Aftas.

The Sevillan emir al-Mu'tamid had been wounded in the first clash but his personal example of valor had rallied the al-Andalus forces in the difficult moments of the initial Castilian charge led by Alvar Fañez.

Those killed include a very popular imam from Cordoba, Abu-l-Abbas Ahmad ibn Rumayla.

The battle is a decisive victory for the Almoravids but their losses mean that it is not possible to follow it up.

Yusuf has to return prematurely to Africa due to the death of his heir.

Castile suffers almost no loss of territory and is able to retain the newly occupied and psychologically important city of Toledo.

However, the Christian advance will be halted for several generations while both sides regroup.

Alfonso appeals for help to the rest of Christendom in the face of the Almoravid threat, and a small expedition is organized as a result; these proto-crusaders’ do not reach Alfonso's lands, instead wasting their energies and resources in an unsuccessful siege of the Muslim outpost of Tudela.

Yusuf ibn Tashfin besieges Aledo but is forced to retreat by the arrival on the scene of the troops of King Alfonso VI.

A string of Christian victories under Rodrigo Diaz de Vivar and successful Christian incursions into Moorish territory compels Tashfin’s return to Spain in June of 1089 at the head of a large army.

Joined in battle by some of the petty Moorish rulers, he battles Alfonso’s forces with no success, and withdraws to North Africa.

The Islamic Abbadid dynasty ruling in Spain falls when the Almoravids storm Seville in November 1091, and al-Mutamid of Seville meets a similar fate as have the emirs of Granada and Málaga.