Muslim scholars believe that while the Koran was revealed over a period of 23 years the Night of Power is considered the night in which the first revelations of Islam and the prophethood of Muhammed began. This night is in celebration of the arrival of the Koran. The whole Night of Power, from sunset to dawn, is the holiest night of the year. It is believed that there are groups of special angels who are only seen on the Night of Power. These angels perform special purposes.