Coincidence?

As I was finishing up The Other Side of Light in November, I noticed that part of the premise of the book was vaguely like a part of Rome's history, the Vestal Virgins. There's a lot to these women, and I had heard of them briefly in the book 13 Little Blue Envelopes. Basically, six women were chosen to keep the sacred fire of the goddess Vesta alight. In order to do this, the Vestal took a thirty-year vow of chastity and if she broke that vow, she would be punished by being buried alive. My book focuses on a line of women who have to keep a lantern alight and in order to do so, much remain unmarried and childless. That's where the similarities ended... or so I thought.

Tonight, I had some free time and thought, I'd really like to know more about the Vestal Virgins. Wouldn't it be cool to take some inspiration from their true story and insert it into my novel? So I began to Google. What I found actually had me going, "Oh, my God" aloud more than a few times.

Before I point out the similarities, remember that all I knew of the Vestals story was what I posted above. I'd never done any further research on them.

The similarities: Vestals: The sacred fire of Vesta, which is fundamental to the security of Rome, can never, ever go out. TOSOL: The dual lanterns, which keep the world in balance, can never, ever go out.

Vestals: Women chosen as Vestals are free of the "social obligation" of marrying and having children in order to devote themselves to the study and duty of the fire. TOSOL: The keepers of the lanterns are not permitted to wed or have children, as they may prove a distraction from training and duties of keeping.

Vestals: The College of Vestals was disbanded and the fire extinguished by a leader named Theodosius I. TOSOL: The lanterns are extinguished by the leader of the society that watches over my MC's family line, who also disbands the keepers. (Sadly, his name is Christopher and not Theodosius or any variant on the name.)

Vestals: The women selected begin their training before puberty, around ages six to ten. It is now that they are sworn to celibacy. TOSOL: Training begins anywhere from ages eight to ten. The trainee understands that she will never get married.

Vestals: The women serve ten years as a student, ten as a Vestal, and ten as a teacher. TOSOL: The girls first train under the current keeper, then take over the duties themselves, and then train the next keeper.

Vestals: To be allowed to serve, they must be in good mental and physical shape, without any deformities. TOSOL: Lyddie is given a mental test to record her intellect as well as her deep-seated fears. If she fails the test, she will be pronounced unfit to do the job and her family will be shamed.

Vestals: If a Vestal broke her vow of chastity, which would lead to the fire going out (because she was neglecting he duties), she was put into an underground room with a few day's worth of food and water and then the steps were pulled up and the entry sealed over with dirt. She was buried alive, but giving her limited provisions allowed the government to say that she went willingly to her death. TOSOL: Lyddie's mother is accused of neglecting her duties due to going against the rules by marrying and having children. As punishment, she is kept in an underground room with very limited food and water for eleven years.

Vestals: Killing a Vestal (even if it was because she broke her vows) by spilling her blood was forbidden. TOSOL: Four women in the story break their vow in some way. All are killed in a bloodless manner.

I was so freaked out by all of these similarities... has this ever happened to anyone else?