Why was the Fatimid proclamation in Baghdad in 1057–59 only temporary?

The Fatimid proclamation in Baghdad (1057–59) was only temporary primarily because the Fatimids were unable to provide the necessary military support to sustain the effort.1

The proclamation was initiated by a dissident general, Arslān al-Muẓaffar al-Basāsīrī, who occupied Baghdad and recognized the Fatimid caliph al-Mustanṣir as the legitimate leader. However, the movement faced several critical obstacles:12

• Lack of Support: The Fatimids failed to send adequate reinforcements to secure the general's position in Iraq.12
• Seljuq Intervention: The Seljuq Turks, who were staunch supporters of the Abbasid caliphate, intervened militarily. They drove al-Basāsīrī out of Baghdad, killed him in 1060, and reestablished Abbasid supremacy.123
• Religious Opposition: The Fatimid Ismāʿīlī doctrine was fundamentally at odds with the Sunni majority, making their claim to universal Islamic leadership unacceptable to the broader population and the rising powers of the era.1

Ultimately, this failure marked a significant turning point, signaling the beginning of the decline for both Fatimid power and influence.1