The statement that is true of the Umayyads is: The Umayyads expanded into Spain.
To elaborate:
- The Umayyad Caliphate, which existed from 661 to 750 CE, did expand into the Iberian Peninsula (modern-day Spain and Portugal), establishing Al-Andalus.
- The Umayyads did impose taxes on non-Muslims (the jizya) as part of their governance.
- The Umayyad capital was Damascus, not Baghdad. Baghdad became a cultural center during the Abbasid Caliphate, which succeeded the Umayyads.
- The Umayyad Caliphate did not decline due to a Mongol invasion; that was more relevant to the later Abbasid period, as the Mongols invaded in the 13th century, long after the Umayyad Caliphate had fallen.