When a war ends, often two countries will sign a treaty, which is a contract where both sides agree to behave a certain way. Treaties are used for many reasons, like creating alliances or preventing nuclear weapons from being built.
The Latin root of treaty is tractare, which means “handle.” When two nations sign a treaty, they decide to handle things according to rules defined in their agreement. However, treaties are not always permanent, and can be broken if one side changes their mind. When white Europeans were settling in the United States, they made many treaties with Native Americans, and every single treaty was eventually broken, some even less than a day later.