Roman Republic and Roman Empire
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| Varied over unit lifetime.
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| Burnum, Dalmatia (9-70) Vindonissa, Germania Superior (70-101) Brigetio, Pannonia Inferior (101-104) Durostorum, Moesia Inferior (104-5th century)
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| Claudia Pia Fidelis Pia V Fidelis V Pia VI Fidelis VI
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| Julius Caesar, Augustus, Roman Emperors
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| Neptune, she-wolf lactating the twins
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| Gallic War -Against the Nervians -Alesia Caesar's civil war -Dyrrhachium -Pharsalus Liberators' civil war -Philippi Antony's civil war -Actium Second Bedriacum Batavian rebellion Dacian Wars Bar Kokhba's revolt Issus Vexillationes of the 11th participated in many other campaigns.
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| Julius Caesar Augustus Septimius Severus
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Legio XI Claudia Pia Fidelis (faithful and loyal Claudian legion) was a Roman legion. XI Claudia dates back to the two legions (the other was the XIIth) recruited by Julius Caesar to invade Gallia in 58 BC, and it existed at least until early 5th century, guarding lower Danube in Durostorum (modern Silistra, Bulgaria). The emblem of this legion is not recorded; it could have been, as well as of all Caesar's legions, the bull, possibly the she-wolf lactating the twins.
The XIth and XIIth legions were levied by Caesar for his Helvetii camapign in 58 BC. The legion fought in the Battle against the Nervians, and probably fought at the Siege of Alesia too. During the civil war, the Eleventh legion fought for Caesar at the Battle of Dyrrhachium and at Pharsalus. The legion was disbanded in 45 BC, and its veterans were offered lands at Bojano, which received the name of Bovianum Undecumanorum, "Bovianum of the members of the eleventh".
Following Augustus' raise to power
The XIth was recontituted in 42 BC by Augustus (at the time known as Octavian), to fight in the civil war against the assassins of Caesar. The XIth fought in the Battle of Philippi, and then sent back to Italy to quell with a revolt at Perugia. It was probably involved with the fight against Sextus Pompeius, who had seized Sicilia.
The Eleventh was sent to the Balkans, but after the major defeat at the Battle of Teutoburg Forest (AD 9), Augustus redistributed the legions on the Northern frontier, sending the XIth at Burnum, Dalmatia (modern Kistanje), together with the VIIth.
Second half of 1st century
In 42, thethe governor of Dalmatia, Lucius Arruntius Camillus Scribonianus, revolted against Emperor Claudius. The Eleventh and the Seventh sided with the Emperor, and put down Scribonianus' rebellion. Claudius awarded each of the two loyal legions with the title Claudia Pia Fidelis.
In the Year of the Four Emperors (69), the XI, the VII (which had moved from Burnum in 58) and the XIV Gemina sided with Otho. A subunit of the Eleventh moved to partecipate to the Battle of Cremona between Otho and his opponent Vitellius, but arrived late on the battlefield, and was sent back to Dalmatia by the victorious Vitellius. When the commander of the Eastern army, Vespasian, claimed the purple, the XIth sided with him, fighting in the Second Battle of Bedriacum, which marked the beginning of the rule of Emperor Vespasian.
Towards the end of the 1st century, Claudia fought on the eastern bank of the Rhine (73/74); it also took part to Domitian campaign against the Chatti in 83.
In 193, after the assination of Caracalla, several claimant for the purple raised; among these there was the governor of Pannonia Superior, Septimius Severus, who gained the support of the XIth. The Claudia did not take part to Septimius march on Rome, but fought with Severus, together with I Italica, against his rival Pescennius Niger. Severus besieged Byzantium, crossed the Cilician Gates, and defeated Niger at the Battle of Issus. It is possible that XI Claudia fought also during the Parthian campaign of Emperor Severus, conquering the Parthian capital of Ctesiphon (198).
Third century and beyond
During the clash between Emperor Gallienus and the Emperor of the Gallic EmpirePostumus, XI Claudia fought for the first, receiving the titles Pia V Fidelis V and Pia VI Fidelis VI ("Five/Six times faithful and loyal").
While still camped in Durostorum, some vexillationes of the Eleventh fought around the Empire: in 295, a mobile subunit is in Egypt, while in 298 another is in Mauretania.
