The Market Revolution, which occurred in 19th century United States, is a historical model which argues that there was a drastic change of the economy that disoriented and coordinated all aspects of the market economy in line with both nations and the world. Charles Grier Sellers, a leading historian of the Market Revolution, portrays it as a highly negative development that marked the triumph of capitalism over democracy. He argues that this was one of the most significant transformations of America within the first half of the nineteenth century— indeed, the defining event of world history— the evolution from an agrarian to a capitalist society. Sellers observes: