The Christian domed basilicas built in Sicily after the Norman Conquest also incorporate distinctly Islamic architectural elements. They include hemispherical domes positioned directly in front of apses, similar to the common positioning in mosques of domes directly in front of mihrabs, and the domes use four squinches for support, as do the domes of Islamic North Africa and Egypt. In other cases, domes exhibit Byzantine influences with tall drums, engaged columns, and blind arcades. The influence of the domed mosques of the Aghlabids has been cited to explain the design of the domes; representative examples of Islamic domes from North Africa can be seen in the Al-Hakim Mosque and the Great Mosque of Sousse.