It goes without saying that the Vestals were perfect images of Roman beauty. Candidates were chosen between ages six and ten from among Rome's best families and, if a replacement was needed the most likely candidate was chosen by lot in an open assembly and then "taken" -- led away by the hand like a war prisoner being taken into slavery -- by the High Priest, the Pontifex Maximus. (Some males were also "taken" for other priestly orders. Brides also were normally "taken" and led away as prisoners and became, in legal terms, the property of the male head of the husband's household.) Vestal candidates had to be without physical or mental flaw. At first there was only one Vestal Virgin in Rome, chosen according to legend by Numa Pompilius, Rome's second King (or perhaps by Romulus) for a term of five years. But shortly thereafter there were two, one and a spare: two were needed to tend the sacred fire kept burning in the Temple of Vesta twenty-four hours a day in the ancient inherited ritual. Their duties expanded, and two more had been added by Plutarch's time (second century AD), and there were six In the third and fourth centuries. The cult was ended and the temple closed by the Emperor Gratian in 382AD, and the last recorded Vestalis Maxima or Chief Vestal, Coelia Concordia, died twelve years later.
Once the system had become fully established, that is, in the Empire period, Vestal Virgins served for thirty years -- ten to learn the duties, ten to perform them, and the final ten to groom a newly chosen Vestal to be a successor. Throughout her thirty years a Vestal dressed and was expected to act with the decorum and dignitas of a Roman bride on her wedding day, and that meant, specifically, before losing her virginity on her wedding night. At the end of their thirty-year terms as priestesses, they could either retire or stay on. In retirement, they could finally enter a real marriage, or, if they wanted to, they could just fool around, and they could do so without risking the death by burial alive and starvation that they might face if they had illicit relations while in office (it happened only on very rare occasions). Clearly, new Vestals were not often inaugurated in the normal run of things: even in the later period when there were six vestals, there should be only two openings in any ten-year period, unless a priestess died or was caught fooling around. Most Vestals who did retire lived quite comfortably -- they had a reasonable pension plan and could have amassed wealth in the form of gifts and endowments (but not fees) they had received during their time in the Temple. One of the additional functions that gradually accrued to the Vestals was custodianship of wills, and it became traditional to remember the Vestals in any such testaments deposited in the Temple of Vesta. Such financial independence meant that a retired Vestal had no need for a husband unless she wanted one. Retired Vestals, by the way, were considered to be a good catch in marriage.
The Vestals originally had a modest bungalow in eastern end of the Forum next to their goddess's round temple, which had been built so to represent the earliest round hearths/huts in the area. But in in 13 or 12 BC, Augustus became High Priest (after Lepidus, the previous Pontifex Max and Augustus's former colleague in the second Triumvirate, finally died). Augustus didn't want to move from his fancy new Palatine Hill digs down into the the Domus Regia, traditional High Priest's residence next to the Vestals' house, so he the Regia over to the Vestals and had it rebuilt to incorporate their traditional residence. That gave the Vestals the 84 room Atrium Vestae in which they lived from that point onward. Augustus, meanwhile, to keep himself on good terms with the goddess, had a small shrine to her built next to his Palatine palace -- he wasn't about to take the chance of abandoning the tradition that the High Priest always lived next door to Vesta. Unfortunately the ruins of the Atrium Vestae have been closed to the public since late 1997, because some arches were discovered to be ready to collapse. There is a promise that the ruins will eventually reopen, but for now, the only way to really see them -- and then at a distance -- is from above, on the rim of the Palatine.
P.S.: The "animation" of things or forces, mentioned in the first paragraph, above, is a characteristic of "primitive" religions that are classified as "animistic". Romans thought of the fire as a living goddess, Vesta. We still so some of this "animating": according to the popular American song from the Broadway and movie musical "Paint Your Wagon", · "the rain was Tess / the fire was Joe / and they called the wind Maria." (Mariah Carey's parents got the spelling wrong.)
P.S. 2: Vestals, like their male priestly counterparts were first invested, then inaugurated, and finally ordained. Although those words are now sometimes used interchangeably, they had specific meanings derived from their Latin roots. Investiture was the putting on of the ceremonial garb -- a bridal gown for a Vestal Virgin. Inauguration was the work of Augurs, who were priests that checked to see if the act and the day were suitable by watching the flight and actions of birds -- the "au" in the words augury and inauguration comes from the Latin word "avis" meaning bird. Ordination was the process by which the candidate was accepted into the order of priests or priestesses.
P.S. 3: The round "Temple of Vesta" in the Forum Boarium that's listed on some maps, guides, and Internet sites was actually dedicated to Hercules and was misidentified merely because its shape superficially resembles that of the Vesta Temple in the Roman republican Forum.
On the Internet: The Vestals are the only ancient Roman religious order that have really broken the threshold of modern common knowledge, so it is not surprising that they are over-represented on the Internet. Everything from insurance companies and law firms (wills?) to women's fantasy baseball teams uses the name Vesta or Vestal Virgins on the net. There is also a lot of misinformation about the Vestals from "new age" popular religion and philosophy sites and from college sororities (which were not in my memories bastions of virginity.)
Here are some good links:
The About.com ancient history site's "Six Vestals" site: http://ancienthistory.about.com/homework/ancienthistory/library/weekly/aa111400a.htm?terms=a1
The Bates College (Maine, USA) "Vestalia" site (with links to other sites): http://www.bates.edu/~mimber/Rciv/vestalia.htm
"Vestal Virgins" from the University of Kentucky -- Quotations from Plutarch and Aulus Gellius: http://www.uky.edu/ArtsSciences/Classics/wlgr/wlgr-religion408.html
Pictures of the Temple of Vesta -- what we see today are the ruins of the temple as it was rebuilt by Emperor Septimus Severus in 205 AD, after the last of several fires that brought down the temple: http://wings.buffalo.edu/AandL/Maecenas/rome/t_vesta_for_rom/thumbnails_contents.html, and http://www.geocities.com/Athens/Pantheon/9013/Vesta.html
Pictures of the Atrium Vestae, which, as mentioned above, has been closed to visitors for the past three years: http://www.siba.fi/~kkoskim/rooma/pages/FAVESTAE.HTM