Information on Guru Nanak:
Sikhism was founded by Guru Nanak Dev, who was born in 1469 to a Hindu family. After four epic journeys (north to Tibet, south to Sri Lanka, east to Bengal and west to Mecca and Baghdad), Guru Nanak preached to Hindus, Muslims and others, and in the process attracted a following of Sikhs (disciples).
Religion, he taught, was a way to unite people, but in practice he found that it set men against one another. He particularly regretted the antagonism between Hindus and Muslims.
Guru Nanak's most famous saying is, "There is no Hindu, there is no Muslim, so whose path shall I follow? I shall follow the path of God."