Guru Nanak, born as Nanak on 15 April 1469 – 22 September 1539.
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He is also known as Baba Nanak, was the founder of Sikhism and is the first of the ten Sikh Gurus.
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His birth is celebrated worldwide as Guru Nanak Gurpurab on Katak Pooranmashi, i.e. October–November.
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Nanak is said to have travelled far and wide across Asia teaching people the message of ik onkar (One God).
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Nanak's words are registered in the form of 974 poetic hymns, or shabda, in the holy text of Sikhism, the Guru Granth Sahib.
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Nanak's sanctity, divinity, and religious authority had descended upon each of the nine subsequent Gurus.
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The fundamental beliefs of Sikhism, articulated in the sacred scripture Guru Granth Sahib, include faith and meditation on the name of the one creator.
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The critical event of his life in Sultanpur, in which he returned after three days with enlightenment, also supports this belief.