Evidence of pacifism goes as far back at 600 BC in India through Hinduism and Jainism. Pacifism extended to everyone, human and non-human. In ancient Greece, in the mid 400's BC, the idea of pacifism only extended to individuals in individual situations. For example, stealing Aristotle's wine after beating him would be completely against the Greek moral ideals. The idea also branches through Aristotle's own value ethics, whereas what is morally right is based on reason. Beating someone would be considered unreasonable by him. Aristophanes even wrote about a woman going on a nonviolent strike against the Peloponnesian war, which he featured in one of his plays. Pacifism also came into being in early Italy, inspired by the God of Peace, Panda. The Hopi tribe in North America had a generally nonviolent outlook on life.
Religiously, Jesus was a pacifist. In the story of the Sermon on the Mount, he makes clear that violence is wrong and unnecessary. For example, the ideas of loving your neighbor as yourself or turning the other cheek. Taoists even believe in the coming of an age of peace.