Guru Nanak (1469–1539), the founder of Sikhism, was a visionary saint and social reformer from Punjab. Through his divine revelations and travels across India and beyond, he preached the oneness of God, equality of all human beings, and rejection of caste and ritualism. His devotional hymns, known as Japji Sahib and other shabads, emphasised honest living, sharing, and remembrance of God. Guru Nanak laid the foundation of Sikhism and transformed the spiritual and social landscape of India through his message of universal brotherhood.