This 'Predatory' Legion was founded some time after the decisive Battle of Actium in 31 BC, by the newly-named Emperor Augustus. It's likely that it initially fought in Augustus' campaigns against the Cantabrians in Spain, from 25-13. After Augustus' son-in-law and future-Emperor Tiberius annexed Raetia in 15 BC, the Legion was based there, at Regina Castra (Regensburg). In 6 AD, it was one of many Legions led by Tiberius against the Marcomanni in Czechia, and it soon afterwards suppressed a rebellion in Pannonia. After the Teutoburg Forest disaster in 9 AD, the Legion was redeployed to Germania Inferior to be based at Xanten with the V Alaudae Legion, guarding part of the Rhine. It fought again under Tiberius when he was Emperor in his Germanic campaigns. In 21, parts of the Legion aided in suppressing the Turoni rebellion in Gaul. Twenty years later, it was used by Caligula in his Germanic war. After Claudius' invasion of Britain in 43, the Legion garrisoned Strasbourg and Vindonissa in Germania Superior, defending strategic Alpine passes against a possible Germanic invasion of Italy. During the chaotic period of 68-69, the Legion was the most important element in the Army of Vitellius during his bid for the throne, and successfully marched on Rome before Vespasian's superior forces made him Emperor. It was afterwards part of an expeditionary force that recovered the Rhineland from the rebellious Batavians. Its base was at Mainz, in Germania Superior. In 89, when the Governor of that Province revolted against Emperor Domitian, the XXI Rapax Legion supported him, but the Legions in Germania Inferior put down the revolt. The Legion was sent to Pannonia, where war against the Germanic tribes of the Middle Danube was imminent. It was there that the Sarmatians destroyed the Legion in 92. Its emblem was the capricorn.