Who were the first people to believe in transmigration of the soul?

The belief in transmigration of the soul, or metempsychosis, is often attributed to ancient Indian religions, particularly Hinduism and Buddhism, where it is an integral part of their philosophical frameworks. Additionally, the concept was present in ancient Greek philosophy, notably in the teachings of Pythagoras and Plato. These early thinkers suggested that the soul moves from one body to another across different lifetimes, influenced by moral actions in previous lives.