Here's a breakdown of its history:
* Old French: The phrase "à Dieu" was used in Old French as a farewell greeting, implying a wish for God's protection.
* Middle English: The phrase was borrowed into Middle English as "adieu," retaining its meaning of a formal farewell.
* Modern English: "Adieu" is still used today, though it is considered somewhat archaic or formal. It is often used in literature or in situations where a more dramatic farewell is desired.
Interesting Note: The phrase "à Dieu" was also used in a more literal sense, meaning "to God's care." This was used to express a hope that someone would be safe or that they would be successful in a dangerous undertaking.