Imagine a place where the government and the church are one and the same, the only religion allowed is the official church of the government, and anyone who dares to contradict the church (and state) is jailed or even executed.
That was the the reality of England in the early 1600s, where the Church of England ruled with an iron hand. However, some people sought to break away from the Church of England to make religion simple and "pure" again -- free of government control. This group became known as the Puritans.
Although the Puritans tried to change the religious climate in England, it soon became clear that the church was too powerful to challenge. Hence, they sought other solutions that would allow them to practice religion in their chosen way. The New World offered that possibility, so the Puritans made plans to leave their homeland for America.
Two ships, the Speedwell and the Mayflower, were procured for the journey to the New World, and the Puritans gathered the possessions they'd need for their pilgrimage -- food, clothing, weapons, tools and seeds to plant crops once they were settled in their new home.
There were many delays, however, and the Speedwell was deemed not seaworthy for the perilous voyage. As a result, some Pilgrims, as they came to be known, stayed behind, while others crowded aboard the Mayflower -- setting off for the New World in September of 1620.
After an arduous, six-week journey, which some of the Pilgrims did not survive, the Mayflower landed at Plymouth, north of Cape Cod, Massachusetts. The Pilgrims set foot in the New World on December 11, 1620 -- finally free to practice their religion.