Legio undecima Claudia ("Claudius' Eleventh Legion") was a legion of the Imperial Roman army. 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 the early 5th century, guarding lower Danube in Durostorum (modern Silistra, Bulgaria). The emblem of the legion is not known; it could have been, as all of the Caesar's legions, the bull or possibly the she-wolf lactating the twins.
Legio XI Claudia, along with Legio XII Fulminata, was a Roman Legion levied by Julius Caesar in 58 BC in Cisalpine Gaul, for his war against the Nervians. They likely were present at the Siege of Alesia. After his campaigns in Gaul, civil war broke out between Julius Caesar and Pompey, both of whom were triumvirs, and in January, 49 BC, Caesar invaded Italy with Legio XI serving in his army. They fought in 48 BC at Dyrrhachium and Pharsalus, but were disbanded in 45 BC and settled in Central Italy around the area of Bovianum Undecumanorum.
Legio XI was reconstituted in 42 BC by Octavian for the civil wars. They served under the command of the second triumvirate consisting of Octavian, Mark Antony, and Marcus Aemilius Lepidus against Brutus and Cassius, who had assassinated Julius Caesar. The Legion was present at the Battle of Phillipi in 48 BC, following which they were dispatched to Perugia in Italy to suppress a local revolt. They likely also served with Octavian in Sicily against Sextus Pompeius.