thumb|upright=1.5|The [[Great Cameo of France, from around 23 AD, pictures several members of the Julio-Claudian dynasty]]
Around the start of the Common Era, the family trees of the gens Julia and the gens Claudia became intertwined into the Julio-Claudian family tree as a result of marriages and adoptions. Augustus, born Gaius Octavius and named primary heir of his grand-uncle Julius Caesar, would become the first Roman emperor and also the founder of the reigning Julio-Claudian dynasty in Rome.
Descendancy of the emperors of the Julio-Claudian dynasty
The Julio-Claudian dynasty was the first dynasty of Roman emperors. All emperors of that dynasty descended from Julii Caesares and/or from Claudii. Marriages between descendants of Sextus Julius Caesar and Claudii had occurred from the late stages of the Roman Republic, but the intertwined Julio-Claudian family tree resulted mostly from adoptions and marriages in Imperial Rome's first decades. Note that descendancy of the Julii Caesares before the generation of Julius Caesar's grandfather is in part conjectural, but as presented by scholars.