The fact that Trotsky lived in Coyoacán made it a meeting place for communists. In 1938, Trotsky wrote the manifesto "Towards a Free Revolutionary Art," which Breton and Rivera both signed. A rift appeared between Rivera and Trotsky when the monthly Marxist magazine, "Clave" (Key) was launched. In August 1940, Ramón Mercader assassinated Trotsky at his home in Coyoacán.