Ancient Philipoppolis had close links with Rome even before the Romans conquered it in 72 A.D. and renamed it Trimontium, 'the City of the Three Hills'.   Not long afterwards, the city became an important stop on the 'Via Diagonalis', the road connecting the Bosphorus with Central Europe. Roman rule took into account the existing societal norms, allowing Thracian aristocrats to become Roman citizens and participate in government, while ordinary Thracians remained free to practise as artisans and farmers. 

When Emperor Constantine the Great (306-337) moved the capital of the Empire to Constantinople (today's Istanbul), Plovdiv began to occupy a important position close to the heart of the Empire. The mid-end of the 4th century saw the Barbarians invaders gaining ground and the end of the Roman Empire, as it split into two - Eastern and Western, ruled respectively from Constantinople and Rome. 

Various sites remain that bear witness to Plovdiv's role in antiquity and allow the visitor to imagine what splendour the city must have known under Roman rule: the Ancient Theatre at the top of Plovdiv Old Town, the Ancient Stadium, Odeon and Forum in the new town as well as the recently renovated Small Basilica and a part of the Roman viaduct. All have been restored so that visitors can see as much as possible of buildings that were hidden under later layers for centuries and have only been uncovered in the last century.