How did empresse Matilda die 1167?

Empress Matilda, the daughter of King Henry I of England, died in 1167 due to natural causes, likely related to her long-standing health issues. She had been involved in a civil war for control of the English throne, known as The Anarchy, which may have taken a toll on her health. Matilda passed away at the age of around 65 at her residence in Rouen, Normandy. Her death marked the end of her direct contest for the throne, and her son, Henry II, would later become king.