Constantine Lips Monastery (Fenari İsa Mosque): On Aksaray Vatan Street, Monastery of Constantine Lips (Fenari Isa Mosque) was built by Admiral Constantine Lips, 'Moni tu Libos', in 907 AD, by giving his name. Gravestones and old materials, brought from Kyzikos (Erdek), were used in the construction of the monastery by processing, and the usage of glazed tiles in the decoration is the first for Byzantine architecture.
The Greek cross planned church was dedicated to Theotokos Panachrantos, the Immaculate Mother of Jesus.
Whether a small hospital was added by Empress Theodora in 1282, the main modification is the church, to the south, dedicated to John the Baptist, where the members of Palaiologos family were buried.
In the first instance, Empress Theodora, died in 1304, and was buried in the funeral chapel of John the Baptist Church. Kazasker (high military judge) Fenarîzade Alaeddin Ali Efendi converted the southern church of the monastery into a masjid in 1496.
During the reign of Sultan Murat IV, Sheikh Isel Mahvi transformed the northern church into a zawiya. The domes and pulleys of the masjid, converted into a mosque in 1650, were rebuilt in 1830. The structure, abandoned after the fire of 1918, has continued to serve as a mosque following restoration work between 1960 and 1963. The graves, under the structure, were damaged during the period when the mosque was not in use. This monument is one of the most beautiful examples of the 13th century Byzantine brickworks.