A Vestal Virgin entered the order as a girl between six and ten years old and owed it a minimum term of thirty years: ten learning her duties, ten performing them, ten teaching the next generation, after which she was technically free to leave and marry, though few did. The six Vestals tended the perpetual fire of Vesta in the Roman Forum, a flame that was never permitted to go out, and among them one held the senior position of Vestalis Maxima, chief Vestal, with primary responsibility for the order's religious and disciplinary conduct.
Occia held that senior office for fifty-seven years, very nearly double the minimum term expected of an ordinary Vestal, an unbroken span of service that the historian Tacitus singled out by name when he came to record her death in 19 CE, describing her as having presided over Vesta's rites for fifty-seven years with unblemished purity. A tenure that length meant Occia had served through the reigns of Augustus and into that of Tiberius, giving her an institutional continuity across one of the most consequential transitions in Roman political history, the founding of the Principate itself, carried out from within an office whose religious duties were themselves unchanged by it.
Vestals held a legal standing unlike any other Roman woman's: freed from a father's or husband's authority, permitted to make a will and give evidence in court, and honored with a lictor and a reserved seat at public games. Occia would have held all of that standing for nearly six decades, longer than most Roman men held any single office or magistracy in a lifetime.