Fully preserved and well restored now is the Roman Rotunda, tranformed into the early Christian church of "St. George"; it now stands behind the Sheraton hotel. Attila took the city by storm in the 5th century. After his death, the Byzantine Empire recovered it. It became part of the Eastern Roman Empire ntill the early 9th century AD. WHen the Danubian kingdom of Bulgaria was founded in 681 AD, many Bulgarian khans coveted Serdica. But it was only in the year of 809 that Khan Kroum succeeded in conquering and including it in the Bulgarian territory. The new name of the city was changed to Sredetz, which in the parlance of that time meant "middle, or centre". In actual fact its location gave it all grounds to be considered the centre of the Balkan Peninsula. Thus the city existed until the year 1018 AD when the Bulgarian lands fell under Byzantine rule and the city was renamed Triyaditza, which in Katerevoussa Greek meant "between mountains".

The city was repeatedly besieged and attacked by Hungarians, Serbs and Crusaders. After the liberation of Bulgaria from Byzantine rule it was re-included in the confines of the country. Its name was now Sophia. The "St. Sophia" church which stands to this day next to the St. Aleksander Nevski memorial cathedral gave the city its present-day name.

Sofia quicly expanded and became a centre of handicrafts and trade. New buildings and numerous churches were built in the city and the neighbouring villages, the best known of these is the Boyana church with world-famous mural paintings.

Sofia fell under Ottaman rule in 1382. In some documents of that time the city was described as a place of particular charm, which evoked the admiration of the conquerors. Irrespective of that, the Turkish authorities' neglect rapidly changed the apperance of the orderly city. Christian churches became derelict and crumbled away, Turkish administration buidlings, mosques, baths and covered markets rose in their place. Five centuries of Ottoman rule changed Sofia beyond recognition. Only recent excavations open to the world the true picture of the city such as it was during its eventful history of many centuries. Few buildings of the Ottoman period have been preserved, the most interesting being the "Bayna Bashi" mosque with and impressive minaret which stills stands, the public baths near the Sheraton hotel, the big mosque (Buyuk Jami) without minaret, which has been turned into a National Museum of Archeology, and the "Black Mosque" reconstructed into a Christian church names "St. Sedmochislenitsi" (Saints Cyril and Methodius and their five disciples) in Graf Ignatieff Street. The Turkish administration recognized the advantageous location of Sofia as a crossroads and important centre of the Balkan Peninsula, and the city's developement as a place of handicrafts and trade was promoted. During the 17th century it grew into the largest marketplace of the Balkans, and in the 18th century a stone-paved highway linked it with Europe and Asia minor. During the 19th century the first railway crossing the Balkans reached Sofia as part of the famous Orient Express. Sofia as part of the famous Express. Sofia became the administrative centre of a "sancak" (pronounced "sandjak"), a large administrative ket importance to the Ottoman Empire. After Serbia won its its independence in the 19th century, the Sofia "sancak" remained on the border. The city was repeatedly attacked and ransaked by the unruly warlords of those times called "Kurdjali", who periodically laid waste to some of its surrounding settlements.

During the Bulgarian National Revival and liberation struggle, Vassils Levski, a key revolutionary names the Apostle of Freesom, soncsidered Sofia as one of the centres of a future uprising, and he created revolutionary comittes in it. He was arrested and brought to Sofia of all places, and hanged in 1873. Sofia was liberated from Ottoman rule on January 4, 1878. The city had 12,000, but it was favourable strategic location made it suitable for a capital of the Principlitly of Bulgaria. In a couple the population increase nearly ten-fold. And at that time the city was modernized for the times. Sofia took the apperance of a European city, although signs of the East remained. The most oriental sights were the markets.