Peace efforts during World War I
Peace efforts during World War I were made mainly by Pope Benedict XV, US President Woodrow Wilson and, from 1916, the two main members of the Triple Alliance (Germany and Austria-Hungary) to bring the conflict to an end. European socialists, taking advantage of their relations on opposing sides through the Political International, also tried to open up the prospect of peace.
Source: Wikipedia — Peace efforts during World War I (CC BY-SA 4.0)