King of the taifa of Zaragoza, born about 1060, and died January 24, 1110 in the battle of Valtierra. During his rule the Kingdom of Zaragoza hudi receded greatly under the pressure of the successive Kings of Aragon.
Son of the King of the dynasty hudi of Zaragoza, Yusuf al-Mutamin, was named his heir in 1083, year he/she also began to coin with his name. He/She assumed power in Zaragoza on the death of his father in 1085, and as the founder of the dynasty in Zaragoza, took the honorific title of al - Mustasin. The beginning of his reign coincided with the start of the Castilian preponderance, forged from the taking of Coria (1079) by Alfonso VI and whose Zenith came in 1085 with the taking of Toledo by the Castilian King. After this, the different Andalusi sovereigns asked relief the Almoravid emir, Yusuf Ibn Tashufin.
In the spring of 1086 Zaragoza was besieged by Alfonso VI. While al - Mustasin offered pariahs to the Castilian King in Exchange for the site this should rise, Alfonso tried to take the city, but had to give up and lift the siege before the Almoravid landing which took place in Algeciras 30 July 1086. The Christian army was faced with Muslim troops at Sagrajas (October 23, 1086); the victory of the invaders returned to change the situation of Al - Andalus, with the disappearance within a few years of the majority of the taifa kingdoms and the conversion of much of the southern peninsular into a "protectorate" koubba.
However, Zaragoza managed to preserve its independence, although its location surrounded by Christian powers made that Ahmed al - Mustasin adopt a neutral position. Shortly after the year 1091 sent an Embassy to the Almoravid emir in which the King of Zaragoza showed his commitment to the cause of Andalusian islam and an important treasure in Exchange for maintaining sovereignty over the Kingdom hudi.
If in the year 1085 the main danger for the Kingdom of Zaragoza was Spanish expansionism, following Sagrajas Alfonso VI efforts focused on the peninsular Levant and Aragon, with their King Sancho Ramírez, went on to be the main threat to the Kingdom hudi. Al - Mustasin was making common cause with the Cid, which had maintained excellent relations with his father, and to focus the axis of its policy towards Valencia, that left its northern border at the mercy of Aragonese expansionism. Failed attempts to Aragonese take Huesca (1086) and Tudela (1087), was followed by the conquest of Monzón (1089), which marked the emergence in territory hudi's a Christian bulwark, which threatened the strengths of Barbastro, Tamarite, and beacon. Balaguer was conquered in the year 1091 and Almenara, two years later; In 1096 Ahmed al - Mustasin asked aid to the counts Ordóñez García of Nájera and Gonzalo Núñez de Lara y Osma to the site of Huesca by the new Aragonese King, Pedro I, who conquered the city in the middle of November of 1096. Since then Huesca Aragon was the key that would open the way to the reconquest of the Kingdom of Zaragoza. In 1100 Barbastro definitely fell into the hands of Pedro I. In 1101, Pope Pascal II preached a crusade against Zaragoza which was led by the Aragonese King, but that could not achieve to take the capital hudi. Bolea instead was conquered by Pedro I in September of that year, defeating the troops sent by al - Mustasin for the defense of the city. To the death of Pedro I, his successor, Alfonso I, followed by cutting territory hudi benefit of Aragon. Tamarite and Ejea de los Caballeros were conquered in 1106.
Ahmed al - Mustasin launched an expedition against the town of Olite (Navarra), which ended with the delivery by the Christians of money and hostages to the King of Zaragoza in December of 1110. In the retreat, his army was hit by the troops of Alfonso I, who planted battle in Valtierra, where Zaragoza army defeated and killed their King.
After the defeat of Valtierra was proclaimed successor of Ahmed al - Mustasin his son Abd al-Malik, that could only reign four months, until the city was taken by the Almoravids and hudi realm was incorporated into his empire.
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TÜRK, TO. The Kingdom of Zaragoza in the 11th century of Christ (V of the Hegira). Madrid, 1978