He belonged to and eventually led the Democratic-Republican party. "(1792-1824), a party created in opposition to the Federalist party—specifically, to the Washington administration's fiscal policies and pro-British foreign policy. Organized by James Madison and Thomas Jefferson with the aid of George Clinton and Aaron Burr, the Democratic-Republicans brought together former Antifederalists and moderate Federalists. They wanted weaker federal government, with most power assigned to the states, an economic policy favoring agriculture, and a foreign policy favoring the French Revolution. In the election of 1796 Thomas Jefferson was their candidate against Federalist John Adams; Adams was elected president and Jefferson, vice president. In 1800 Jefferson and the Democratic-Republicans defeated Adams and the Federalists, who also lost control of Congress. After the disintegration of the Federalist party in 1816, the Democratic-Republicans divided into several groups. They, and the former Federalists, became the short-lived National Republican party, the Whig party, and the Democratic party. The Democratic-Republicans called themselves Republicans after Jefferson's election and are still sometimes referred to as the first Republican party, but it bears no relation to the present Republican party." Just google Democratic-Republican Party for more info...