Islam is a monotheistic religion that was founded in the 7th century by the Prophet Muhammad. It is the second-largest religion in the world, with over 1.8 billion adherents. Islam is based on the teachings of the Quran and the Sunnah, which are the words and actions of the Prophet Muhammad. The core beliefs of Islam include belief in one God, angels, prophets, and the Day of Judgment. Muslims also believe in the Five Pillars of Islam, which are the five duties that all Muslims must fulfill. These include the declaration of faith, prayer, charity, fasting, and pilgrimage to Mecca.