In Gallic times the city was important as a crossing point of the Loire. Becoming part of the Roman Empire during the 1st century AD, the city was named “Caesarodunum” (“hill of Caesar”). The name evolved in the 4th century when the original Gallic name, Turones, became first “Civitas Turonum” then “Tours”. It was at this time that the amphitheatre of Tours, one of the five largest amphitheatres of the Empire, was built. Tours became the metropolis of the Roman province of Lugdunum towards 380–388, dominating the Loire Valley, Maine and Brittany. One of the outstanding figures of the history of the city was Saint Martin, second bishop who shared his coat with a naked beggar in Amiens. This incident and the importance of Martin in the medieval Christian West made Tours, and its position on the route of pilgrimage to Santiago de Compostela, a major centre during the Middle Ages.
In the 6th century Gregory of Tours, author of the Ten Books of History, made his mark on the town by restoring the cathedral destroyed by a fire in 561. Saint Martin’s monastery benefited from its inception, at the very start of the 6th century from patronage and support from the Frankish king, Clovis, which increased considerably the influence of the saint, the abbey and the city in Gaul. In the 9th century, Tours was at the heart of the Carolingian Rebirth, in particular because of Alcuin abbot of Marmoutier.
In 732 AD, Abdul Rahman Al Ghafiqi and a large army of Muslim horsemen from Al-Andalus advanced 500 kilometres (311 miles) deep into France, and were stopped at Tours by Charles Martel and his infantry igniting the Battle of Tours. The outcome was defeat for the Muslims, preventing France from Islamic conquest. In 845, Tours repulsed the first attack of the Viking chief Hasting (Haesten). In 850, the Vikings settled at the mouths of the Seine and the Loire. Still led by Hasting, they went up the Loire again in 852 and sacked Angers, Tours and the abbey of Marmoutier.