Tanaquil was the wife of Tarquinius Priscus, fifth king of Rome.
She had four children, two daughters and two sons. One of the daughters (Tarquinia) became the wife to Servius Tullius, when he became the successor.
The daughter of a powerful Etruscan family in Tarquinii, Etruria, Tanaquil thought her husband would make a good leader, but since he was the son of an immigrant, he would not be able to gain power in Tarquinii, where they lived. Knowing this, Tanaquil encouraged him to move to Rome, which was not at the time dominated by a strong local aristocracy. Her strong prophetic abilities helped her to install Tarquin as king and later Servius Tullius as the next king. While on the road to Rome, an eagle flew off with Tarquin's hat and then returned it to his head. Tanaquil interpreted this as a sign that the gods wanted him to become a king.
Tanaquil's prophecy was eventually realized for Tarquin - he eventually became friends with King Ancus Marcius, who made Tarquin guardian of his children. When the king died before his children were old enough to become successors to the throne, Tarquin used his popularity in the Comitia to be elected the fifth king of Rome. He ruled from 616 to 579 BCE.
Tanaquil also played a role in the rise of Servius Tullius, the sixth king of Rome. Raising him as her own child, Tanaquil believed Servius would be the next successor to the throne. Her dreams would be realized when, one day Servius was sleeping and his head was surrounded with flames. The fires danced around his head without hurting him and when Servius awoke, the fire disappeared. Taking this as an omen, Tanaquil knew Servius would one day be king. When Tarquin was murdered, Tanaquil hid his death from her subjects, instead telling them that Tarquin appointed Servius as a temporary king until he got better. After gaining the people’s respect and commanding the kingship, Servius and Tanaquil announced Tarquin’s death. Tanaquil had a daughter, (Tarquinia) who married Servius Tullius, and two sons, Lucius Tarquinius Superbus and Aruns Tarquinius, who would marry Tullia, the daughter of Servius Tullius.
According to Festus, she changed her name to Gaia Caecilia (called Gaia Cyrilla in Boccaccio's On Famous Women) when she arrived at Rome, although some Roman historians also commonly spelled her name Caia Caecilia or Caia Cyrilla. Under this name she is the mythical source of various Roman wedding customs. She was remembered as a skillful artisan in the art of working with wool. Queen Gaia was so much admired by the Romans of her day that it was a public decree that any new bride entering their royal palace would announce their name as "Gaia" when asked. This was said to be an omen of future frugality for these women and showed the simple living style of the time period. Pliny says that a statue was dedicated to her as Gaia Caecilia in the temple of Semo Sancus.