Medina, is a modern city in the Hejaz region of western Saudi Arabia, and the capital of Al Madinah Province. An alternative name is Madinat Al-Nabi. The Arabic word madinah simply means "city." Before the advent of Islam, the city was known as Yathrib but was personally renamed by Muhammad.The burial place of the Islamic Prophet Muhammad, it is the second holiest city in Islam after Mecca. Medina is critically significant in Islamic History as Muhammad's final religious base after the Hijrah and the location of his death in 632 AD/11 AH. Medina was the power base of Islam in its first century, being where the early Muslim community developed, first under Muhammad's leadership and then under the first four caliphs of Islam: Abu Bakr, `Omar, `Othman and `Ali.In fact, Year 1 of the Islamic calendar is based on the year of the emigration (or Hijra) of Muhammad and his original followers from Mecca to the city of Medina in 622 AD/1 AH. The Maliki madhab places emphasis on ulema and scholars originating in Medina.Medina is reportedly home to the three oldest mosques in Islam which were built in the days of Muhammad, namely Al-Masjid an-Nabawi, Quba Mosque, and Masjid al-Qiblatain.Similarly to Mecca, entrance to the sacred core of Medina is restricted to Muslims only; non-Muslims are not permitted to enter nor are they allowed to cross through the city center.Muslims believe that the final chapters of the Qur'an chronologically were revealed to the Prophet in Medina and are called Medinan surahs in contrast to earlier Meccan surahs.