It was drafted by the Pilgrims who crossed the Atlantic on the Mayflower ( ship ) , looking for the freedom to practice Christianity according to their own determination . It was written by the colonists , later together known to history as the Pilgrims , who crossed the Atlantic aboard the Mayflower . Almost half of the colonists were part of a separatist group seeking the freedom to practice Christianity according to their own determination and not the will of the English Church .