The very first International Women's Day was launched the following year by Clara Zetkin on 19 March (not 8 March). The date was chosen because on 19 March in the year of the 1848 revolution, the Prussian king recognized for the first time the strength of the armed people and gave way before the threat of a proletarian uprising. Among the many promise he made, which he later failed to keep, was the introduction of votes for women.
http://www.internationalwomensday.com/
