Before people started living in cities and towns, they used to live in small groups called tribes. These tribes sometimes fought with other tribes because they needed more land or resources like food and water. They also fought because they might have had a problem with each other or just wanted to prove that they were stronger.
When tribes fought, they often used weapons like spears, bows and arrows, and even rocks. The battles were usually small and only involved a few people from each tribe. Sometimes these battles happened just between two people. These battles were not organized like wars that happened later on when people lived in cities.
As people started living in cities, they started making bigger armies and using more advanced weapons like swords and chariots. These armies were led by kings and generals who planned out the battles and sent soldiers into battles. They fought for land, resources, and to conquer other cities.
So, war existed even before civilization, but it was different than the wars that happened later on. It was mostly fought between small groups of people who lived in tribes and it was not as organized or planned as the wars that happened after civilization.