They were soldiers. They would work for their employer to protect his property goods and family. Samurai fought over land in Japan around 1100 and 1200
well... long ago in ancient japan there were different types of warriors and samurais were one of them they would protect the valley or town from ninjas and other retarded bandits who think they can...
Samurai don't become Samurai, they are born in to a samurai clan. Generally both parents come from a Samurai family, but the father has to be a Samurai if the son is to be a Samurai.