The Plymouth Separatists cooperated with the Puritans who settled the Massachusetts Bay Colony in 1630. Although the Puritans had originally hoped to purify and reform the Church of England, in New England they accepted the congregational form of church government established by the Pilgrims.
One reason that they have two parties is because peoples points of views we all don't think alike so we were given more options. It also gives us a chance to vote for the better of the two finalist.
Great Britain established the worlds largest empire. =)