The Junius family was very ancient and noble, with both Patrician and Plebeian branches. In the Republic, the most famous of them were the two Junii Bruti, which produced the founder of the republic and the famous assassin of Caesar. In the early Empire, the most famous was the patrician Junius Silanus branch. The Silani were in close contact with the Julio-Claudian emperors and even related to the imperial family by blood, some being direct descendants of Augustus.

The very first Junius known to Roman tradition was the patrician Lucius Junius Brutus, founder of the Republic. But one must realize that Marcus Junius Brutus, Caesar's assassin, was by no means his descendant, as some wished to believe, but came from the plebeian family of the same name.