Tiy was a commoner until the day she became the Great Wife of the mighty Egyptian monarch, Amunhotep III.  Her father was the High Priest of Min, the local god of a small Egyptian town; her mother held high office as well in the same temple, but these were titles of middling importance. Those who still cling to the Heiress Queen Theory argue that she must be of royal descent, but there is no proof one way or another.

A large statue in the king's mortuary temple in Thebes shows the royal couple on an equal scale. (According to Egyptian artistic convention this implied equality of importance.)  In a private tomb scene she is pictured in the form of a sphinx trampling enemies, a task one usually associates with kings, not queens.  Tiy is the first woman to adopt as part of her regalia the horn and disc of the goddess Hathor.  Shortly after the marriage the King ordered a two mile long lake constructed in her honor.  They sailed the length of the lake in the royal barge for all to see; a few years later a second lake was built for her.  As the flood waters receded every year thereafter farmland was available to produce money that was Tiy's to spend as she wished.

Tiy had six children, including a daughter Beketaten, born when Tiy was in her mid to late forties. The parentage of Ancient Egypt's best known Pharaoh, Tutankhamun, is a hotly debated topic. Tiy is certainly one of the contestants, but there is no proof.  What is certain is that her son, Akhenaten, succeeded to the throne and promptly began a religious revolution.  He believed there was only one God---an idea that earned him the epithet The Heretic and led the Egyptians to erase his memory until the Nineteenth Century.

As did all of the New Kingdom pharaohs, Amunhotep had rather a large harem. He married his daughter Sitamun and gave her the title King's Great Wife.   Marrying his daughter was not too uncommon (see the page Brother-Sister Marriage), but it was rather unusual to have two women alive and bearing the title King's Great Wife at the same time.   On those occasions when Tiy and Sitamun are portrayed together, Sitamun is called merely King's Wife.  When the daughter is pictured alone, she carries the higher title.

It would appear from copies of letters from foreign courts that Tiy was a woman of considerable power.  Indeed, it has been suggested that Tiy was the defacto ruler of Egypt for the last few years of her husband's reign.