Antonia is the female form of the Old Roman family name Antonius – one of the oldest family names known to the ancient Roman Republic and shared by both the patrician and plebian classes. In fact, the Antonius clan is so ancient, most etymologists believe it is of Etruscan origin (a now-extinct civilization of ancient Italy long ago absorbed by the Latins). Since the Etruscan language is also extinct, the meaning of Antonius seems to be forever lost to history. According to folk etymology, the “th” was added to Anthony in the later Middle Ages in order to connect the name to the Greek “anthropos” (“of a man, manly”) thus forcing a new etymology.
In Antiquity, girls born to the Roman Antonius patrician families were given the name Antonia in keeping with Ancient Rome’s three-part naming system. The family name was most famously born by Roman politician and military general Marcus Antonius (83-30 BC) who claimed direct descent from the mythological Anton, son of Hercules. Eventually, as the Roman Empire lost its power and standing in Europe (c. 5th century) and as Europe descended into the Dark Ages, the names Antony/Antonia seemed to be on their way to extinction had it not been for a couple important saints keeping the name fresh in the minds of Christians.
Saint Antony the Great (“The Father of All Monks”) was a 3rd/4th century glorified hermit. His life was memorialized by a Greek biographer shortly after his death; a written work which maintained widespread appeal throughout Europe up through the Middle Ages. St. Antony was not the first monk (as he’s often credited for being), but he was the first to live as a hermit for more than a decade deep in the deserts completely cut off from civilization. He was greatly admired for his ascetic life and religious discipline (apparently St. Antony successfully endured and overcame through prayer all sorts of supernatural temptations flung at him by the Devil). Needless to say St. Antony was one of the most revered saints in medieval Europe. He is also the patron saint against infectious diseases (which were rampant in the Middle Ages), particularly skin diseases that are still referred to as “St. Anthony’s Fire” (e.g., shingles). Folks prayed to him for relief and his name was often bestowed on children as a protective measure.
Having an even greater impact on the successful endurance of the Anthony names in medieval times was the 12th/13th Saint Anthony of Padua, a Portuguese Franciscan priest (one of the quickest to be canonized a saint upon his death). The most popular of St. Francis of Assisi’s disciples, Anthony of Padua was known for his zealous evangelizing of scripture (a subject matter on which he had expert knowledge). Greatly revered, St. Anthony enjoyed a huge cult following after his death and his name was popularized throughout Europe in various ethno-linguistic and gender variations (he is also the patron saint of lost articles and lost people). Antonia is the female form of Anthony used among the Italians, Spanish, Portuguese, English, Germans and Scandinavians. The French have a history of using Antoinette. Tonia and Tonya developed later as English short forms of Antonia.