Rennes is the administrative capital of the French department Ille-et-Vilaine. Before the French revolution, prior to the integration of the Duchy of Brittany into the Kingdom of France, Rennes was the capital of the duchy, with the other historical capitals of Brittany's Ducal period being Nantes and Vannes. It has a long history due to its location at the confluence of two rivers and its proximity to the bordering regions from which arose various challenges to the borders of Brittany.
The eastern Armorican people of Redones founded Condate —an ancient Celtic word meaning confluent— at the confluence of the Ille and Vilaine rivers and made it the capital of a territory that extended to the Bay of Mont Saint-Michel. The name of the city of Redon also reflects that of the Redones. Early in the 1st century BCE, they adopted the Greek and Roman practice of issuing coinage, adapting the widely imitated gold staters of Philip II of Macedon, in the characteristic Celtic coin metal alloy called billion. Without inscriptions, as the Celtic practice was, the Redones coinage features a charioteer whose pony has a human head. Large hoards of their coins were unearthed in the "treasure of Amanlis" found in June 1835 and that of Saint-Jacques-de-la-Lande, discovered in February 1941. The museum at Rennes contains a large representative collection.
They joined the Gaulish coalition against Rome in 57 BC, which was suppressed by Crassus. The following year, Roman emissaries were held hostage by the Redones, which obliged Julius Caesar to intervene in Armorica and suppress the rebels, and the following year to cross the Channel to discourage further support of the Redones by the Britons. In 52 the Redones responded to the call of Vercingetorix to furnish a large contingent of warriors
In the Roman era, Condate became Condate Riedonum, capital of Civitas Riedonum.
The oldest known Rennais is Titus Flavius
