Major world religion founded by Muhammad in Arabia in the early 7th century AD. The Arabic word islam means surrenderspecifically, surrender to the will of the one God, called Allah in Arabic. Islam is a strictly monotheistic religion, and its adherents, called Muslims, regard the Prophet Muhammad as the last and most perfect of God's messengers, who include Adam, Abraham, Moses, Jesus, and others. The sacred scripture of Islam is the Qur'an, which contains God's revelations to Muhammad. The sayings and deeds of the Prophet recounted in the sunna are also an important source of belief and practice in Islam. The religious obligations of all Muslims are summed up in the Five Pillars of Islam, which include belief in God and his Prophet and obligations of prayer, charity, pilgrimage, and fasting. The fundamental concept in Islam is the Shari'ah, or Law, which embraces the total way of life commanded by God. Observant Muslims pray five times a day and join in community worship on Fridays at the mosque, where worship is led by an imam. Every believer is required to make a pilgrimage to Mecca, the holiest city, at least once in a lifetime, barring poverty or physical incapacity. The month of Ramadan is set aside for fasting. Alcohol and pork are always forbidden, as are gambling, usury, fraud, slander, and the making of images. In addition to celebrating the breaking of the fast of Ramadan, Muslims celebrate Muhammad's birthday (see mawlid) and his ascension into heaven (see mi'raj). The 'Id al-Adha festival inaugurates the season of pilgrimage to Mecca. Muslims are enjoined to defend Islam against unbelievers through jihad. Divisions occurred early in Islam, brought about by disputes over the succession to the caliphate (see caliph). About 90% of Muslims belong to the Sunnite branch. The Shi'ites broke away in the 7th century and later gave rise to other sects, including the Isma'ilis. Another significant element in Islam is the mysticism known as Sufism. Since the 19th century the concept of the Islamic community has inspired Muslim peoples to cast off Western colonial rule, and in the late 20th century fundamentalist movements (see Islamic fundamentalism) threatened or toppled a number of secular Middle Eastern governments. In the early 21st century, there were more than 1.2 billion Muslims in the world.