English: Islamic religious buildings traditionally were lit with glass lamps, generally called mosque lamps, that hung from chains. In 16th-century Turkey, it was common to make mosque lamps from glazed ceramic and to pair them with round or oval ornaments. Such ceramic pieces were of little use as lighting fixtures. They may have functioned, however, as acoustic devices, hung in groups to soften the echo of voices in the prayer hall. Mosque lamps were also symbols of divine light, and, therefore, of God's presence in the place of prayer, while the ornamental spheres symbolized the orb of heaven. This beautiful Iznik Rhodianware ceramic lamp is adorned with the names of God and the Prophet- Allah and Muhammad- followed by those of the first four leaders of the Islamic caliphate, or government: Abu Bakr, Umar, Uthman, and Ali. The inscribed names, written in a large Arabic script called thuluth, confirm that the lamp was intended for symbolic as well as aesthetic purposes.