Jefferson is an icon of individual liberty, democracy, and republicanism, hailed as the author of the Declaration of Independence, an architect of the American Revolution, and a renaissance man who promoted science and scholarship. The participatory democracy and expanded suffrage he championed defined his era and became a standard for later generations. Meacham opined, that Jefferson was the most influential figure of the democratic republic in its first half-century, succeeded by presidential adherents James Madison, James Monroe, Andrew Jackson, and Martin Van Buren. Jefferson is recognized for having written more than 18,000 letters of political and philosophical substance during his life, which Francis D. Cogliano describes as "a documentary legacy ... unprecedented in American history in its size and breadth."