what is the style of arch found at the great mosque at cordoba
an upper semi-circular arch a lower horseshoe arch
title: Horseshoe arch text: major work, the Great Mosque of Córdoba. This style of horseshoe arch then spread all over the Caliphate and adjacent areas, and was adopted by the successor Muslim emirates of the peninsula, the taifas, as well as by the Almoravid dynasty, Almohad Caliphate, and the Nasrid Kingdom of Granada, although also lobed, round, pointed and multifoil arches were also used at that time. The Mozarabs also adopted this style of arch into their architecture and illuminated manuscripts. Horseshoe arches were also used in the Great Mosque of Kairouan (the earliest surviving part being the mihrab of 862-863), the Mosque of title: Mosque–Cathedral of Córdoba text: a hall for teaching and for Sharia law cases during the rule of Abd al-Rahman and his successors. The Great Mosque of Córdoba exhibited features and an architectural appearance similar to the Great Mosque of Damascus, which may have been used as a model. The building is most notable for its arcaded hypostyle hall, with 856 columns of jasper, onyx, marble, granite and porphyry. These were made from pieces of the Roman temple that had occupied the site previously, as well as other Roman buildings, such as the Mérida amphitheatre. The double arches were an innovation, permitting higher ceilings than title: Mosque–Cathedral of Córdoba text: would otherwise be possible with relatively low columns. The double arches consist of a lower horseshoe arch and an upper semi-circular arch. The famous alternating red and white voussoirs of the arches were inspired by those in the Dome of the Rock and also resemble those of the Aachen Cathedral, which were built almost at the same time. Horseshoe arches were known in the Iberian Peninsula since late Antiquity, as can be seen on the 3rd-century "Estela de los Flavios", now in the archaeological museum of León. A centrally located honeycombed dome has blue tiles decorated with stars. The edifice title: Islamic architecture text: been in use by the Byzantines. In Moorish architecture, the curvature of the horseshoe arch is much more accentuated. Furthermore, alternating colours were added to accentuate the effect of its shape. This can be seen at a large scale in their major work, the Great Mosque of Córdoba. The Great Mosque of Damascus (completed in 715 by caliph Al-Walid I), built on the site of the basilica of John the Baptist after the Islamic invasion of Damascus, still bore great resemblance to 6th and 7th century Christian basilicas. Certain modifications were implemented, including expanding the structure along the transversal axis title: Córdoba, Spain text: Cercadilla. From 784- 786 AD, Abd al-Rahman I built the Mezquita, or Great Mosque, of Córdoba, in the Umayyad style of architecture with variations inspired by indigenous Roman and Christian Visigothic structures. Later caliphs extended the mosque with more domed bays, arches, intricate mosaics and a minaret, making it one of the four wonders of the medieval Islamic world. After the Christian reconquest of Andalucía, a cathedral was built in the heart of the mosque, however much of the original structure remains. It can be found in the Historic Centre of Córdoba, a recognized World Heritage Site. Built in 930