August

12 August 2161, by Earth's Gregorian calander, was the date that the Articles of the Federation were signed by United Earth, Vulcan, the Andorian Empire, Tellar, and Alpha Centauri in San Francisco, officially establishing the existence of the United Federation of Planets. Amongst the signatories were such noted figures of the 22nd Century as Jonathan Archer of Earth and Soval of Vulcan. Thereafter, every 12 August was celebrated as Federation Day. (Last Full Measure.)

12 August 2161 also the date that Archer, then a captain in the United Earth Starfleet, gave a historic speech at the signing in which he declared that it had been UE Starfleet's mission, and would become the Federation Starfleet's mission, to continually expand the Federation's knowledge -- to "explore strange new worlds; to seek out new life and new civilizations; to boldy go where no man has gone before." ("Zero Hour" [ENT].)