According to the founder's inscription above the west entrance, the The Church of Panagia Chalkeon was built in 1028 by the protospatharios Christopher, katepano of Longobardia, and his wife, son, and two daughters.
The ground plan is that of a classic 'cross-in-square-form' typical of Macedonian-period architecture, with four columns and three domes, one central and two over the narthex. The entire building is built of bricks, which gave it the popular nickname 'Red Church'. The exterior is enlivened with a variety of arches and pilasters, elements which can be traced to Constantinopolitan influence. The use of arches with several setbacks gives the building a 'sculpted' appearance. A marble cornice runs around the whole church, giving the building distinctive upper and lower sections. The lower section is more spare, while the upper section is decoratively distinguished by half-columns between arches, and saw-tooth courses where the wall meets the roof.
The interior of the church is divided into three sections: The narthex, the naos (the central square of a ‘cross-in-square’ plan), and the sanctuary.
The narthex is covered by three barrel vaults and has an upper gallery that was perhaps used as a sacristy. There was never, however, a stair leading up to it. Anna Tsitouridou speculates that it may have been accessed by a ladder through a now closed up arched window on the northwest corner of the church.
In the naos, four light grey marble columns form a square and support the arches of the four barrel-vaults that make up the arms of the cross going out. In the center of the square is the dome. Pendentives between the arches create a circular base for the dome above. The dome is 3.8m wide and its height is 5.3m. It is octagonal, containing sixteen windows in two rows, one atop the other. The arms of the cross can be clearly seen on the exterior, with saddle back roofs over their great barrel vaults, and triangular pediments emphasising their ends. Domical vaults cover the four bays between the arms of the cross, completing the square of the naos.
Though founders' tombs are usually placed in the narthex of their churches, at Panagia Chalkeon the tomb believed to be Christopher the founder's is found in a niche (an arcosolium) in the north wall of the naos.
The painted decoration of the church is not in a good state of preservation. It is nonetheless of great interest because the bigger part of the wall-paintings was executed at the same time as the foundation of the church, according to a second founder's inscription, which forms part of the painted decoration, on the intrados of the triumphal arch in the sanctuary, and refers to the same founders. The original painted decoration of the church represents two styles that have their origins in Constantinople. The iconographic program of the church includes scenes from the life of Christ (the Dodekaorton and the Passion), and is of interest in that the Ascension is placed on the main dome. The side walls of the sanctuary have two scenes in which is unfolded the divine Eucharist.
The original 11th century painted decoration on the lower parts of the north and south walls, and on the west side of the nave appears to have been replaced in the Palaiologan period. Of these paintings, all that survive are a few remains of the Dormition of the Virgin, some figures of individual saints, and three of the twenty-four stanzas of the Akathistos Hynnos. The Last Judgment is painted on the vault and parts of the east and west walls of the narthex, in a majestic composition. This, too, belongs to the initial decoration of the church.References:
The Church of Saint Demetrius, or Hagios Demetrios, is the main sanctuary dedicated to Saint Demetrius, the patron saint of Thessaloniki. It is part of the site Palaeochristian and Byzantine Monuments of Thessaloniki on the list of World Heritage Sites by UNESCO since 1988.
The first church on the spot was constructed in the early 4th century AD, replacing a Roman bath. A century later, a prefect named Leontios replaced the small oratory with a larger, three-aisled basilica. Repeatedly gutted by fires, the church eventually was reconstructed as a five-aisled basilica in 629–634. This was the surviving form of the church much as it is today. The most important shrine in the city, it was probably larger than the local cathedral. The historic location of the latter is now unknown.
The church had an unusual shrine called the ciborium, a hexagonal, roofed structure at one side of the nave. It was made of or covered with silver. The structure had doors and inside was a couch or bed. Unusually, it did not hold any physical relics of the saint. The ciborium seems to have been a symbolic tomb. It was rebuilt at least once.
The basilica is famous for six extant mosaic panels, dated to the period between the latest reconstruction and the inauguration of the Byzantine Iconoclasm in 730. These mosaics depict St. Demetrius with officials responsible for the restoration of the church (called the founders, ktetors) and with children. An inscription below one of the images glorifies heaven for saving the people of Thessalonica from a pagan Slavic raid in 615.
Thessaloniki became part of the Ottoman Empire in 1430. About 60 years later, during the reign of Bayezid II, the church was converted into a mosque, known as the Kasımiye Camii after the local Ottoman mayor, Cezeri Kasım Pasha. The symbolic tomb however was kept open for Christian veneration. Other magnificent mosaics, recorded as covering the church interior, were lost either during the four centuries when it functioned as a mosque (1493–1912) or in the Great Thessaloniki Fire of 1917 that destroyed much of the city. It also destroyed the roof and upper walls of the church. Black-and-white photographs and good watercolour versions give an idea of the early Byzantine craftsmanship lost during the fire.
Following the Great Fire of 1917, it took decades to restore the church. Tombstones from the city"s Jewish cemetery - destroyed by the Greek and Nazi German authorities - were used as building materials in these restoration efforts in the 1940s. Archeological excavations conducted in the 1930s and 1940s revealed interesting artifacts that may be seen in a museum situated inside the church"s crypt. The excavations also uncovered the ruins of a Roman bath, where St. Demetrius was said to have been held prisoner and executed. A Roman well was also discovered. Scholars believe this is where soldiers dropped the body of St. Demetrius after his execution. After restoration, the church was reconsecrated in 1949.