This is the period from 1800 through 1815 which includes the administrations of two Democratic-Republican Party presidents, Thomas Jefferson and James Madison. They are commonly called Jeffersonian Republicans. During this time the country nearly doubled in size with the Louisiana Purchase from France. This, in turn, was one of the causes behind the War of 1812, when Great Britain attempted to re-claim her former American colonies.<!Era of good feelings • http://www.ushistory.org/us/23a.asp -->