Complex sentence: The Abbasid continued to promote the Umayyad rectangular hypostyle plan with arcaded courtyard and covered prayer hall, The Abbasid constructed Mosques characterized by their monumental scale and the incorporation of brick construction, stucco ornament, and architectural forms developed in Mesopotamia and regions to the east.
Split into simpler sentences: The Abbasid continued to promote the Umayyad rectangular hypostyle plan with arcaded courtyard and covered prayer hall. They constructed Mosques on a monumental scale and incorporated brick construction, stucco ornament, and architectural forms developed in Mesopotamia, and other regions to the east.