Külliye, the construction of which was ordered in 1378 by İshak Bey, the third-generation ruler of Saruhans Principality during the reign of whom the principality can be said to live its most glorious days, consists of a mosque built on the Northern mountainside of Mount Spil, a madrasa, the Mausoleum of İshak Bey and Çukur Hamam located northwest of the mausoleum. Despite being located farther away from these structures, Manisa Mevlevihane is also considered to be included in the külliye.
The mosque, which has a rectangular plan along its width, is covered with a large dome resting on an octagonal foot system. The minbar of the single minaret mosque, which is made with genuine kundekari technique, is one of the masterpieces of Turkish wood-carving craft in the Principalities Period. Since stone carving was not yet sufficiently developed within the principality of Saruhan during the period the mosque was built, column heads from the remains of buildings of previous periods in the region were used. While visiting the mosque, column heads which are from the Ancient Greek, Roman, Byzantine and Seljuk periods, and which are all different from each other can be seen. The building presents quite an interesting appearance in this respect. Çukur Hamam, which is also included in the külliye, is a unique structure which is separated from other baths built within the period by having a separate section for the use of non-Muslims. Also, it is said that there is a passage leading to Castle Manisa to be used in the presence of a dangerous situation beneath the bath. The existence of such a passage is plausible, since the bathhouse was used by the rulers of that era. Madrasa, which is also called "Fethiye Madrasa", was built by the same architect as a single iwan, two storey structure about ten years after the construction of the mosque. There is a fountain on each side of the crown door of the structure, which is the oldest madrasa of the city.