Ridvan is the greatest festival of the Baha'i Faith, a twelve-day celebration (21 April to 2 May) commemorating the days in 1863 when Baha'u'llah, the faith's founder, first declared to his companions that he was the messenger of God whose coming the Bab had foretold. The declaration took place in a garden on the outskirts of Baghdad, on the eve of his exile to Constantinople; Baha'u'llah named the garden Ridvan, "paradise", and the festival takes its name from it. The occasion is regarded as the most joyful and significant in the Baha'i calendar, marking the open beginning of his mission.
Of the twelve days, the first, ninth and twelfth are holy days on which work is suspended, corresponding to Baha'u'llah's arrival in the garden, the arrival of his family, and his departure. Ridvan is a time of gladness, gathering and hospitality, and it is also the season during which Baha'i communities hold their annual elections: the local and national governing councils (Spiritual Assemblies) are elected during Ridvan, giving the festival an administrative as well as a devotional dimension. As the commemoration of the moment their faith's founder first announced his station, Ridvan is to Baha'is the "King of Festivals", the centre of their year.