Vadomarius (‹See Tfd›German: Vadomar) was an Alemannic king and Roman general, who shared power with his brother Gundomadus. After instigating an indecisive campaign in Gaul against the Romans, Vadomarius and his brother signed a treaty with the Roman emperor Constantius II in AD 356. Encouraged by Constantius II, Vadomarius employed his Alemanni forces in an attack against Julian (Constantius' Caesar who had revolted against his rule). Vadomarius then concluded a treaty with Julian, after which, he unsuccessfully attempted to play the two Roman figures against one another. When Julian was made aware of this, he arrested Vadomarius and banished him to Hispania. His son Vithicabius succeeded him as king. Later, Vadomarius allied himself with Rome under emperors Jovian and Valens, leading his forces against the usurper Procopius and fighting the Persians on Rome's behalf.