The Basilica di San Zeno name rests partly on its architecture and partly upon the tradition that its crypt was the place of the marriage of Shakespeare's Romeo and Juliet. It stands adjacent to a Benedictine abbey, both dedicated to St Zeno of Verona.
St. Zeno died in 380. According to legend, at a site above his tomb along the Via Gallica, the first small church was erected by Theodoric the Great, king of the Ostrogoths. Erection of the present basilica and associated monastery began in the 9th century, when Bishop Ratoldus and King Pepin of Italy attended the translation of the saint's relics into the new church. This edifice was damaged or destroyed by a Magyar invasion in the early 10th-century, at which time Zeno's body was moved to the Cathedral of Santa Maria Matricolare: on May 21, 921, it was returned to its original site in the crypt of the present church. In 967, a new Romanesque edifice was built by Bishop Raterius, with the patronage of Otto I, Holy Roman Emperor.
On January 3, 1117, the church, along with most of the city, was damaged by an earthquake; the church was restored and enlarged in 1138. Work was completed in 1398 with the reconstruction of the roof and of the Gothic-style apse.
Attached to the basilica is an abbey was erected in the 9th century over a pre-existing monastery. Of the original structure, destroyed in the Napoleonic Wars, only a large brick tower and the cloisters survive. It had originally another tower and the abbot's palace. For long time the abbey was the city's official residence of the Holy Roman Emperors. In the 1980s a restoration discovered frescoes from the 12th to 15th centuries.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.