Conversation so far:
when was the united nations founded and why
The UN Conference on International Organization opened in San Francisco, 25 April 1945 and is responsible for maintaining international peace and security.
Why was the United Nations founded?
The United Nations was founded to replace the League of Nations following World War II and to prevent another conflict.

Question: When did the League dissolve?
Self-contained rewrite: When did the League of Nations dissolve?