A variation of Islamic architecture, Moorish style developed somewhere around 11th century. Named after the Moors (North Africans who conquered the Iberian peninsula and other islands – presently Spain, Portugal, etc), Moorish architecture comprises of motifs and their repeat patterns, mainly characterised by the style of arches, intricate calligraphy (chapters from Quran), tile work, vegetative design(tendrils, vines etc.)
Their rich geometric designs had a great influence on the arts and architecture of the Gothic and Renaissance periods. The point of difference between Moorish style and other forms of Islamic architecture is that the former uses rounded shapes than squares or rectangles.
Notable examples representing great Moorish architecture include Mezquita in Spain which is now a Catholic Cathedral, Ben Young Madrassa in Marrakech, Blue Mosque in Istanbul, Imam mosque in Isfahan(Iran), Wazir Khan Mosque in Lahore(Pakistan) and many others.
Images (Clockwise form top) : Mosque–Cathedral of Córdoba via Pinterest; by Naeem Rashid; via Wikipedia; via Flickr by youngrobv