Evidence has been found for the existence of settlements in the area of Troyes as far back as prehistoric times. The first permanent population of peoples were Celtic in origin and were known as the Tricasses, from which derives the name, Troyes. Mention of these tribes has been found in Greek writing dating to the 2nd century BCE. In the first century CE, the name of the settlement changed from Tricasses to Augustobana, reflecting its inclusion in the Roman Empire and its Gallo-Roman constitution. The city was fortified at this time, as it was located in a strategic position.

    The city was subject to barbarian invasions until the 5th century, when a bishop was installed, known as the Bishop of Troyes. Many of the city's religious buildings were built during the 7th century. The city became a part of Charlamagne's Kingdom of France before it splintered and Troyes became part of Western France. The city then fell under the rule of the counts of Champagne, before becoming a part of the Kingdom of France again in 1285.

    The city was involved in the Hundred Years War with England. The treaty of Troyes, signed in the city 1420, was meant to put an end to the strife associated with that conflict.