Continuing up Saint Sophia Street and turning left into Saint Demetrius Street, you will find on your right the apparently modern church of Saint Demetrius. This, the city's largest church, was originally built in the 5th century, when it was considered the most beautiful. It also is a paleo-christian basilica, and has five naves. It was partially destroyed by a fire during the celebrations of Saint Demetrius in 538 and rebuilt, only to be burnt and again rebuilt in the 7th century. The present building was erected after a fire in 1917. Some of the 8th-century mosaics are still to be seen near the choir, one depicting Saint Demetrius as protector of children and another showing him with Leontius (who built the church) and a bishop. Two more show Our Lady and Saint Sergius. Then there is an interesting painting on the south wall. Also there are some of the original pillars of coloured marble with carved capitals. The side-chapel of Saint Euthemios was built about 1303 in the time of the Emperor Andronicus II, by Michael, his Master of Horse. In the crypt, which is on the site of the martyrdom of Saint Demetrius by Galerius, is the so-called Baptistry, near the saint's legendary tomb. From here flowed the sweet-smelling and miraculous healing myro (oil) which attracted pilgrims and caused Saint Demetrius to be known as Myrovlitos.
Going back down Saint Sophia Street it is easy to pick out the Cathedral of Aghia Sophia (Holy Wisdom), standing in Dikastirion Square, by its large green dome, similar to its namesake in Constantinople. This spacious building (dating probably from the 7th century) heralds a change in architecture; the basilica, besides being crowned with a dome, shows the first signs of what was to develop into the Greek Cross plan. This also was used as a mosque. The mosaics were restored by the Turkish government but in 1912 it became a church again. In spite of recent bomb damage and redecoration, the 8th and 11th century mosaics are very impressive. Besides the Madonna and Child in the apse, the great work is the Ascension in the cupola, showing Our Lord seated on a rainbow, surrounded by a ring of angels and apostles alternating decoratively with olive trees. Walk along Hermou Street and turn right up Aristotelous Street into busy, old Dhimarkis Square, where you will find the small red church of Theotokos. It is also known as Panaghia Khalkeon, Our Lady of the Coppersmiths, since it stands where these workers were congregated, as was the custom of the Guild churches. This church, built in 1042, is typical of the Byzantine Greek Cross. Note the frescos of the Apocalypse and Last Supper; also the tomb of Christoforos, the founder.