Medina, officially Al Madinah Al Munawwarah (, , and also commonly simplified as Madīnah or Madinah (, ), is the second-holiest city in Islam and the capital of Medina Province in Saudi Arabia. , the estimated population of the city is 1,488,782, making it the fourth-most populous city in the country. Located at the core of the Medina Province in the western reaches of the country, the city is distributed over , of which constitutes the city's urban area, while the rest is occupied by the Hejaz Mountains, empty valleys, agricultural spaces and older dormant volcanoes. Medina is generally considered to be the "cradle of Islamic culture and civilization". The city is considered to be the second-holiest of three key cities in Islamic tradition, with Mecca and Jerusalem serving as the holiest and third-holiest cities respectively. Al-Masjid al-Nabawi () is of exceptional importance in Islam and serves as burial site of the last Islamic prophet, Muhammad, by whom the mosque was built in 622 CE. Observant Muslims usually visit his tomb, or rawdhah, at least once in their lifetime during a pilgrimage known as Ziyarat, although this is not obligatory. The original name of the city before the advent of Islam was Yathrib (; ), and it is referred to by this name in Chapter 33 (Al-Aḥzāb, ) of the Quran. It was renamed to () after Muhammad's death and later to () before being simplified and shortened to its modern name, (), from which the English-language spelling of "Medina" is derived. Saudi road signage uses and interchangeably. The city existed for over 1,500 years before Muhammad's migration from Mecca, known as the Hijrah. Medina was the capital of a rapidly-increasing Muslim caliphate under Muhammad's leadership, serving as its base of operations and as the cradle of Islam, where Muhammad's Ummah ()—composed of Medinan citizens (Ansar) as well as those who immigrated with Muhammad (Muhajirun), who were collectively known as the Sahabah—gained huge influence. Medina is home to three prominent mosques, namely al-Masjid an-Nabawi, Masjid Qubaʽa, and Masjid al-Qiblatayn, with the Masjid Quba'a being the oldest in Islam. A larger portion of the Qur'an was revealed in Medina in contrast to the earlier Meccan surahs. Much like most of the Hejaz, Medina has seen numerous exchanges of power within its comparatively short existence. The region has been controlled by Jewish-Arabian tribes (up until the 5th century CE), the ʽAws and