Next to the entrance to the Temple of Athena, this poorly maintained 14th-century mosque is a simple structure – a dome on squinches set on top of a square room – that was constructed with materials from a 6th-century-AD church and is one of just two remaining Ottoman mosques of its kind in Turkey (the other is in Bursa, and Hüdavendigar is in fact a poetic name for that city).