The Abbasids established Baghdad as their capital in the 8th century. They were influenced by Persian architectural styles and traditions, adopting features like monumental palaces centered around large courtyards and iwans. The Abbasid caliph Al-Mansur founded the circular planned city of Baghdad, while later caliphs built lavish palaces like Ukhaydir and Samarra, characterized by fortified enclosures, towers, and elaborate decorative elements. The Abbasids established new models of royal architecture and palatial complexes that demonstrated their power and wealth.