The phrase “bury a hatchet” is inspired by a North American Indian Tradition!

On top of hunting and farming, the Natives also helped us create this beloved cliché. To “bury the hatchet” means to create peace. The thought is that when hostilities are no longer needed, weapons, like the hatchet, can be disposed of as well. 

When negotiating peace, the North American Indians would actually practice what we preach. They buried all of their weapons-their scalping knives, clubs, tomahawks-into the ground. 

Apart of just showing good faith, this would also make it impossible for the fighting to continue. Thus came the popular expression; burying the hatchet. However nowadays, the idea of “burying” the hatchet seems counter-intuitive to most people, they would rather dig up the old ones. 

(Source)