Complex sentence: The siege of Baghdad was the last Seljuq attempt to capture Baghdad from the Abbasids, Caliph Al-Muqtafi successfully defended his captial against the coalition armies of Seljuq Sultan Muhammad of Hamadan, and Qutb-adin of Mosul.
Split into simpler sentences: The Siege of Baghdad was the last Seljuq attempt to capture Baghdad from the Abbasids. Caliph al-Muqtafi successfully defended his capital against the allied armies of Seljuq Sultan Muhammad of Hamadan, and Qutb ad-Din of Mosul.