Amenhotep III lavished a good deal of attention on his charming wife. He devoted number of shrines to her, built her a palace, and even built her an artificial lake. During his reign, Akhenaton built his mother a sumptuous shrine.
Tiy enjoyed a good deal of power during her husbandís and sonís reigns. Amenhotep III, although a fine sportsman, lover of outdoor life, and a man of great wealth, was no statesman. Tiy, on the other hand, appears to have been the power behind the throne. She was her husbandís trusted advisor and confidant, played an active role in foreign relations, and was the first Egyptian queen to have her name on official acts. She continued to advise Akhenaton when he took the throne. Her sonís correspondence with Tushratta, the king of Mitanni, speaks of Tiyís political influence, which she wielded in part because at the time royal and noble bloodlines passed through the familyís female members.
Amenhotep III died in year 38 of his reign (1350 BC/1349 BC). But twelve years after his death, she is still mentioned in inscriptions as Queen and beloved of the King. It has been suggested that Akhenaton and his mother acted as consorts to each other till her death. This would be considered incest at the time. Supporters of this theory consider Akhenaton to be the historical model of legendary King Oedipus of Thebes, Greece and Tiy the model for his mother/wife Jocasta.
In an inscription estimated to November 21 of year 12 of Akhenaton' reign (1338 BC), both she and her granddaughter Meketaten are mentioned for the last time. They are thought to have died shortly after that date.
In 1898 archaelogist Victor Clement Georges Philippe Loret (1859 - 1946) discovered a mummy of a Pharaoh that is believed to have been Amenhotep III and along it the mummy of an "Elder Lady". The identification of the Elder Lady with Tiy has found considerable support. Examination of the mummy suggest that the Elder Lady was about sixty years old when she died.
If the year of death was year 12 of Akhenaton's reign (1338 BC this would place her birth around 1398 BC, her marriage to Amenhotep III at the age of thirteen and her becoming a widow at the age of forty-eight to forty-nine years old.