Complex sentence: The Siege of Tabriz took place in 1501 just after the Safavids had defeated the Aq Qoyunlu in the Battle of Sarur, which the Aq Qoyunlus army was 4 times bigger than the Safavid army.
Split into simpler sentences: The Siege of Tabriz took place in 1501 just after the Safavids had defeated the Aq Qoyunlu in the Battle of Sarur. In the preceding battle the Aq Qoyunlus army was 4 times bigger than the Safavid army.