The Eski Imaret Mosque was formerly the Church of the Monastery of Christ Pantepoptes, or, the "All-Seeing Christ." It is located in a historic neighborhood at the summit of the city's fourth hill, and in close proximity to the Zeyrek Church Mosque. The monastery was built by Anna Dalassena, the mother of Alexius I Comnenus (1081-1118), who later retired to an apartment in the monastery. The monastery buildings were handed over to a Benedictine sect during the Latin invasion in 1204; and then were used to house an Ottoman soup kitchen (imaret), hostel (zaviye) and madrasa after the Ottoman conquest at which time the church was converted into a mosque. The Turkish name of the church translates to 'old soup kitchen' and refers to the soup kitchen at the former monastery.
The complex was damaged in fires that swept the shores of the Golden Horn, and the church - which remained - housed the dormitory for a Koranic school in the 1950s. The church is today used as a mosque. It has been restored twice: once in the 1970s by Architect Fikret Çuhadaroglu; and again during an unauthorized restoration in the 1990s.
The Eski Imaret mosque has not been well studied, despite its significance as the only documented 11th century church in Istanbul. To counterbalance the sloped site, the church rests on a cistern, which creates a level platform. It has a Greek cross or cross-in-square plan and is composed of a nave with four vaulted cross-arms around a dome, a sanctuary to the east and an inner and outer narthex to the west. Entered from the west, the outer narthex consists of three bays that are cross-vaulted on the sides and domed at the center. When remains of the broken minaret, attached to the outer narthex for centuries, were removed in 1990, the structure of the uncovered wall revealed that the outer narthex was an open portico until enclosed during the Late Byzantine period. Three archways, one in each bay, lead into the inner narthex, which is slightly narrower and has semi-circular niches at either end. The inner narthex has an upper gallery with lower ceilings, which opens into the nave with triple arched windows. Covered with a dome at its center, the upper gallery has the unique feature of rooms attached at either end that have windows pierced into the barrel vaults of the cross-arms. The nave is as tall as the lower and upper galleries of the inner narthex, and its loftiness is enhanced by the tall drum of its dome. Four piers that support the dome partition the nave into three aisles. The north and south aisles lead into small clover-shaped chapels to the east, that link to the sanctuary. These chapels are designated for the functions of prothesis and diaconicon, respectively. Marble moldings, cornices, and doorframes are the only remaining traces of the original interior.
Exterior views of the church-mosque are obscured by apartment buildings that close in on all sides. Its undulating roofline, obscured by a single flat roof in Ottoman times, was rebuilt in the 1970 restoration. On the east façade, the side chapels are clearly distinguished from the nave and the sanctuary with their lower height and sloping flat roofs. There are occasional decorative brick details on its exterior walls. In 1990, the ground level was lowered on the east, south and west sides of the church, to alleviate moisture problems. The Eski Imaret Mosque is constructed of brick and stone; the brick tiles on its roof are a unique feature among the churches and mosques of Istanbul.