The term "populism" came into use in the late 19th century alongside the promotion of democracy. In the United States, it was closely associated with the People's Party, while in the Russian Empire it was linked to the agrarian socialist Narodnik movement. In the 1960s the term became increasingly popular among social scientists in Western countries, and later in the 20th century it was applied to various political parties active in liberal democracies. In the 21st century, the term became increasingly common in political discourse, particularly in the Americas and Europe, to describe a range of left-wing, right-wing, and centrist groups that challenged the established parties.