The principal motivation behind the establishment of Plymouth Colony in 1620 was the pursuit of religious freedom. A group of English Separatists, known as Pilgrims, sought to escape religious persecution in England and find a place where they could practice their faith freely. After a challenging journey across the Atlantic on the Mayflower, they established the colony in what is now Massachusetts. The settlers faced harsh conditions, but they aimed to create a community based on their religious beliefs and values. This aspiration laid the foundation for early American ideals of religious liberty and self-governance that would evolve over time.