The Five Pillars of Islam ( أركان الإسلام; also أركان الدين "pillars of the religion") are fundamental practices in Islam, considered to be obligatory acts of worship for all Muslims. They are summarized in the hadith of Gabriel. The Sunni and Shia agree on the basic details of the performance and practice of these acts, but the Shia do not refer to them by the same name (see Ancillaries of the Faith, for the Twelvers, and Seven pillars of Ismailism). They are: Muslim creed, prayer, charity to the poor, fasting in the month of Ramadan, and the pilgrimage to Mecca for those who are able. The ritual obligations of Muslims are called the Five Pillars. They are acknowledged and practiced by Muslims throughout the world, notwithstanding their disparities. They are viewed as compulsory for individuals who genuinely wish to pursue a life like that which prophet Muhammad led. Like other religions, Islam holds certain practices to be standard; however, that does not imply that all individuals who regard themselves as Muslims necessarily observe them. Individual participation can vary depending on the individual's faith; for example, not every individual prays every day, keeps the fast, performs the Hajj, or donates extensively to charity. There are also Muslim communities such as Alevis who reject the Five Pillars but follows Four Doors system. Shortly after the Muslim Arabs conquered new terrains, they started raising mosques and castles and commissioning different commemorations and artifacts as articulations of their faith and culture. The religious practice of Islam, which signifies "submission to God", depends on fundamentals that are known as the Five Pillars. Each of the five pillars is alluded to in the Quran, though in various chapters (suwar). Further insights concerning these commitments are given in the Hadith. Though comparable practices were performed in pre-Islamic Arabia and by Jews and Christians at the time of Muhammad, they were changed in the Quran and Hadith, given a carefully monotheistic center, and identified with the life of the Prophet.