An anti-war social movement that emerged at the end of the 19th century.

this is Pacifism.
Public anti-war movement that originated in the US and UK. Pacifism owes its origin to the end of the Napoleonic conflicts in Europe. The heyday of pacifism in the 19th century falls on the 80s and 90s. This movement gathers congresses and encourages countries to resolve their conflicts exclusively in Arbitration Courts. There are calls for disarmament. In the Russian Empire, Count Leo Tolstoy and his moral teaching – Tolstoyism – are considered a bright representative of pacifism.