Sikhism originated in the 15th century in the Punjab region of South Asia by Guru Nanak and his successors. It combines elements of Hinduism and Islam while also having some unique philosophical and theological concepts including belief in one God, the rejection of idolatry and caste system, equality of mankind, and emphasis on living a virtuous life. The religion was further developed and systematized by the 10 Sikh gurus and is guided by the teachings in the Guru Granth Sahib scripture.