The forces supporting Vitellius were divided into two armies for the march on Rome, one of them commanded by Valens, the other by Aulus Caecina Alienus.
Valens' troops took a route through Gaul, probably to recruit additional soldiers, eventually joining with the Vitellian army led by Caecina at Cremona.
Valens and Caecina won a decisive victory, and Otho committed suicide when he heard the news of his army's defeat, allowing Vitellius to make a triumphant entry into Rome.
By this time Valens had recovered from his illness and was on his way to join the army, but before he could reach his men, the Vitellian forces had been defeated by Antonius at the second Battle of Bedriacum.
He put in at Hercules Monoecus (modern Monaco) but was advised not to try to march inland as a procurator named Gaius Valerius Paulinus had raised a strong force from former members of Otho's Praetorian Guard.