Who is The Democratic-Republican Party from The Market Revolution: Jacksonian America, 1815-1846 and what is their importance?

The National Republican party is the successor to the first major political party in the United States, the Democratic-Republican Party of Thomas Jefferson and James Madison. When John Quincy Adams becomes president, the party starts to unravel. Initially the party has represented the democratic, decentralist and agrarian impulse in American politics but has over time become co-opted by a number of different special interests, including the Northern industrial interests it initially opposed. When John Quincy Adams becomes president in 1825, the party basically collapses and has separate candidates for president. Thus ideologically the Democratic-Republicans represent various different strands of American political thought and practice.