bury the hatchet
Defined: to stop arguing and to make peace
Example: After ten years of not talking, the two brothers decided to bury the hatchet.
For some of the Indians of North America, this was one of their peacemaking customs. To mark the end of hostilities, they literally buried hatchets (tomahawks) under the ground. Afterwards, they smoked the peace pipe. This would indicate an end to war.