It was built in 313 BC as a small chapel, over the ruins of a Roman bath. Two centuries later it was reconstructed and expanded by Bishop Leontios. The church was completely destroyed during the great fire of 1917 and it was rebuilt.
The construction lasted over 30 years and it reopened in 1949. It is the city’s most important church and it is dedicated to Thessaloniki’s patron saint. Underneath the church there are catacombs, that were the christians’ refugee during their pogrom by the Romans and also the place where Saint Demetrios became a martyr.