Its strategic importance was early recognized by the Romans, and about 13 B.C. Drusus, the son-in-law of Augustus, erected a fortified camp here, to which the castellum Mattiacorum (the modern Castel) on the opposite bank was afterwards added, the two being connected with a bridge at the opening of the Christian era.
With the object of providing for the transmission of divine and human knowledge to later ages, and of securing it against the tide of barbarism which threatened to sweep it away, he founded two monasteries - Vivarium and Castellum - in his ancestral domains at Squillace (others identify the two monasteries).
Orleansville occupies the site of the Roman Castellum Tingitanum.
Castrum Cerrucium, Castel-sur-Azine (from the neighbouring stream, Azine) and Castellum Sarracenum are suggested derivations, no one of which can be adopted with certainty.
Andernach (Antunnacum) is the old Roman Castellum ante Nacum, founded by Drusus and fortified in the 3rd century A.D.
Chatellerault (or Chatelherault: Castellum Airaldi) derives its name from a fortress built in the 10th century by Airaud, viscount of its territory.
Castellum) was not founded until the beginning of the 5th century by Corc son of Lugaid.