Moslems in Iran and throughout the world mourn for their prophet. Prophet, Mohammad, may peace be upon him passed away eleven years after his migration from Mecca to Medina which marks the beginning of the Islamic calendar. Shia’s second Imam, Imam Hassan (PBUH) was martyred on the same day, around forty years later. Muslims throughout Iran and other countries mourn their passings and remember them on this date. By the time of Prophet Mohammad’s passing, most of the Arabian Peninsula had converted to Islam and he had united into a single Muslim religious entity. Today, there are more than 2.2 billion Muslims in the world. This means that roughly one out of every four person in the world is a Muslim.