How was Henri La Fontaine awarded the Nobel Prize Peace?

Name: Henri La Fontaine.
Country: Belgium.
Date of Birth: 22 April 1854.
Died: 14 May 1943.
Education: Free University of Brussels.
President: Permanent International Peace Bureau, Berne, Switzerland.
Known as: Member, Belgian Parliament.
Noble Prize Year: Nobel Prize for Peace in 1913, because he was the effective leader of the peace movement in Europe.