April 21, 1863: Baha’u’llah declares His Mission to His companions in the Najibiyyih garden outside the city of Baghdad

The arrival of Baha’u’llah in the Najibiyyih Garden, subsequently designated by His followers as the Garden of Ridvan, signalizes the commencement of what has come to be recognized as the holiest and most significant of all Baha’i festivals, the festival commemorating the Declaration of His Mission to His companions. So momentous a Declaration may well be regarded both as the logical consummation of that revolutionizing process which was initiated by Himself upon His return from Sulaymaniyyih and as a prelude to the final proclamation of that same Minion to the world and its rulers from Adrianople … (Shoghi Effendi, ‘God Passes By’)