On May 15, 1911, the US Supreme Court found Standard Oil in violation of the Sherman Act and ordered its dissolution.

Read Standard Oil Co. of New Jersey v. U.S.

On May 15, 1955, the Allied Powers of World War II and representatives of Austria signed the Österreichischer Staatsvertrag (Austrian State Treaty), which re-established Austria as an independent nation for the first time since it was annexed by Nazi Germany in 1938. The treaty explicitly forbade any future attempts to unify with Germany.