Gaius

Gaius is a masculine given name from ancient Rome. It is a Latin praenomen that was widely used from the early Republic through the imperial era. The exact etymology is uncertain, but the form is well attested in inscriptions and literary texts. In modern usage, the name survives in two common spellings: Gaius and Caius.

The name was common across social strata in Rome and appears in the full names of many notable figures. Prominent bearers include Gaius Julius Caesar, the general and statesman who played a central role in the events that ended the Roman Republic; Gaius Marius, a major general and reformer; and Gaius Gracchus, the tribune and reformer, brother of Tiberius Gracchus. The birth name of the first Roman emperor was Gaius Octavius Thurinus, who became Augustus. Other celebrated Gaiuses include Gaius Petronius Arbiter, the author of Satyricon, and Gaius Plinius Secundus (Pliny the Elder). In early Christian literature, a Gaius is mentioned as a host to Paul and as a Christian in Romans 16:23.

Modern usage of the name is largely historical, with Caius functioning as the archaic or scholarly form in English. The variant Caius appears in institutional names such as Gonville and Caius College, Cambridge, named after the 16th‑century physician John Caius (Gaius). The name continues to appear in literature and fiction as a Latinized given name.