This mosque was built on the western skirts of the Ayasuluk Hill on which stand the fortress and the Church of St. John.For topographic reasons its most ostentatious and magnificent face is the west one. It is an interesting point that it was built between the Temple of Artemis and the Church of St. John which belong to previous periods. It almost gives the impression that the temples of three different periods are in competition here. The building measures 51 by 57 metres. There is a row of shops with supporting arches at the lower level of the wall in the west façade. The main entrance on the west is reached by two separate flights of stairs of fifteen steps each mounting from either side.
The mosque was built in 1375 by Aydinoglu Isa Bey. The architect was Dimiçikli Ali from Damascus. We learn this from the inscription over the west portal. The entire west façade is covered with marble. The other faces of the edifice were built in squared blocks of stone. The west portal is framed with edgings in relief and has a protruding pointed arch which is very ostentatious. The windows in this façade are arranged in two rows one above the other. Their dimensions and decorations are different from one another. We can see here the finest examples of the stone workmanship of the period. In the lower row of windows coloured keystones were used and the upper parts of the windows on the left are decorated with stalactitic lines and holy writings. The other faces of the building are without any decoration. On the east is a portal symmetrical with that of the west. This is also called the portal of the sultan. The minaret is destroyed. The entrance on the north façade was in later periods blocked by a stone wall.
Entering the courtyard by the decorative main gate on the west covered by a diagonal vault porticoes encircling the courtyard on three sides and a fountain in the middle meet the eye. We see from the traces on the walls and the rows of columns that the portico was in two tiers. The minaret above the west entrance stands on an octagonal base, is decorated with tiles, and rises up to the external gallery. The top part was knocked down.
The actual place of worship of the mosque lies to the south. This section is entered from the courtyard by a door with three pointed arches set on two columns. In the middle there are two domes set on a pointed arch rising on four large granite columns of nearly one meter diameter. The sides of the domes are covered by two rows of wooden gable roofs. Although the domes were decorated with tiles most of them have disappeared. Of the capitals on the columns three are stalactitic, thus reflecting a characteristic of the period, and one is from the Roman period in composite style. The marble niche for the imam in the south wall is new. It is a copy of the original and was built in 1989. The original niche is in the Kestane Pazari Mosque (the Mosque of the Chestnut Market) in Izmir. It was taken there in the Ottoman period.
This mosque occupies an important place in the history of art because it was there that a second hall for the worshippers was built for the first time and also because it constituted a transitional architecture between the Seljuk and Ottoman periods.