At the junction of Egnatia and Aristotelous Streets, south-west of the Roman agora, stands the Church of the Panagia Chalkeon. It was built on the site of the Megalophoros, Thessaloniki's main agora, near the arcade where the coppersmiths had their workshops, as they still do today.
The inscription on the marble lintel over the west entrance tells us that Christopher, "protospatharios and katepano of Lombardy", together with his wife, Maria, and their children, Nikephoros, Anna, and Katakale, built the church in honour of the Mother of God in 1028. Christopher's tomb is in the middle of the north wall.
The church represents the new type that was evolving at the time of the Macedonian dynasty, the cross-domed church. In the central square four columns support the arches of four barrel-vaults, which in turn hold up the central dome, giving the ground plan and the superstructure the form of a cross. To the east is a tripartite sanctuary and to the west a two-storey narthex, roofed with two smaller domes.
The influence of the architecture of Constantinople is clearly apparent both in the church's type and in the masonry, which is relieved by successive superposed arches and arcades, niches, and engaged columns. A marble cornice runs around the church halfway up the walls, and beneath this there was a decorative strip of coloured ceramic tiles. The exclusive use of brick in the concealed-course technique led to the monument's being popularly known as the "Red Church".
An inscription on the sanctuary barrel-vault tells us that the interior was frescoed when the church was built. A few Christological scenes (the Nativity, the Presentation, the Adoration of the Magi, and Pentecost) survive in the naos, and some liturgical scenes in the sanctuary, where we see the Virgin Platytera, hierarchs, and the Communion of the Apostles. The decision to place the Ascension in the central dome reflects the fact that the church was built as a sepulchral monument. The Second Coming is in the narthex. The wall paintings compare with other such ensembles of the same period, such as those in Hosios Loukas in Phokis, Nea Moni on Chios, Hagia Sophia in Ohrid, Hagia Sophia in Kiev, and monuments in Cappadocia.
The decoration was restored in the Palaiologan era, from which time survive the Dormition of the Virgin, a few scenes from the Akathistos Hymn, and some isolated figures of saints.
In 1430 the church was converted into a mosque and named the Hazancilar (Jamii ("mosque of the coppersmiths"). After the earthquake of 1978 consolidation work was carried out on the monument and the frescoes were conserved.