The tradition of using three names dates back to ancient Rome.
Just like most Americans have a first, middle, and last name, many ancient Romans also used three names, especially upper-class men. (Women typically had two names, and enslaved people were called by just one.) But these ancient monikers weren’t a direct parallel to how we use middle names today. Roman full names started with a praenomen, or personal name, which often came from numbers or months, possibly noting the time or order of birth (such as “Quintus” or “Sextus”). The middle name, nomen gentilicium, came from a person’s gens, a broad family clan based on a patriarchal line. Names then ended with a cognomen, which could reflect a smaller family group or reference a specific attribute, such as a big head, pug nose, or left-handedness. These nicknames were passed down to children, and throughout a person’s life, they could have more than one cognomen.
Some Roman men, particularly aristocrats, had more than three names — often because they were adopted or accepted an inheritance, linking them to additional family members. One senator in the second century CE had a whopping 38 names, six of which came from his father. By the fifth century CE, multiple names had mostly fallen out of use, and after that Roman citizens typically went by just one name. Middle names came back into vogue in Renaissance Italy, when families would give their children Catholic saint names in hopes the saints would protect them. This paved the way for middle names as we know them today, although the practice didn’t catch on in Britain or the United States until the 19th century.