Serdica was an ancient city located in present-day Sofia, the capital of Bulgaria. It was founded in the 1st century AD and became an important center for trade and culture in the Roman Empire. The city was known for its strategic location along major trade routes and its well-preserved Roman ruins, including baths, theaters, and fortifications. Throughout its history, Serdica was influenced by various cultures, including the Thracians, Romans, and Byzantines. It was officially recognized as a city by the Roman Emperor Constantine the Great, who also renamed it Constantinople for a brief period. Today, the archaeological remains of Serdica attract visitors and historians interested in its rich past.