Prior to 1863, several individuals created forms of fencing that could be considered barbed wire. But it was not until 1873 that Henry M. Rose had an idea and had an exhibit of it at the county fair.
With hundreds of miles of fence being built daily the state of Kansas decided to put a law on the fences. If an animal breached or got on to another persons land, the the owner of the animal had to pay for the damage.
The purpose of barbed wire was to make an easy way to keep animals in where you wanted them. They also wanted to hurt the livestock without injuring them so that they would learn there boundaries and not even try to get out eventually.