The term was originally used by the French military to refer to a small reconnoitre group that scouted ahead of the main force. It also became associated with left-wing French radicals in the nineteenth century who were agitating for political reform. At some point in the middle of that century the term was linked to art through the idea that art is an instrument for social change. Only toward the end of the nineteenth did l'art d'avant-garde begin to break away from its identification with left-wing social causes to become more aligned with cultural and artistic issues. This trend toward increased emphasis on aesthetic issues has continued to the present. Avant-garde today generally refers to groups of intellectuals, writers, and artists, including architects, who voice ideas and experiment with artistic approaches that challenge current cultural values. Avant-garde ideas, especially if they embrace social issues, often are gradually assimilated by the societies they confront. The radicals of yesterday become mainstream, creating the environment for a new generation of radicals to emerge.