What is the origin of the phrase carte blanche?

The phrase "carte blanche" originates from French and it literally translates to "blank card" in English. It originally referred to an unconditional authorization or freedom given to diplomats or messengers by a leader or a government. In the 17th century, diplomats would carry "cartes blanches," which were blank, unsigned cards granting them the authority to write their own terms of agreement. Over time, the term evolved to signify unrestricted power, freedom of action, or complete discretionary authority given to someone to act as they see fit.