Nanak is said to have travelled far and wide across Asia teaching people the message of Ik Onkar (ੴ, 'One God'), who dwells in every one of his creations and constitutes the eternal Truth.

[12] With this concept, he would set up a unique spiritual, social, and political platform based on equality, fraternal love, goodness, and virtue.

Most janamsakhis (ਜਨਮਸਾਖੀ, 'birth stories'), or traditional biographies of Nanak, mention that he was born on the third day of the bright lunar fortnight, in the Baisakh month (April) of Samvat 1526.

[20] In as late as 1815, during the reign of Ranjit Singh, the festival commemorating Nanak's birthday was held in April at the place of his birth, known by then as Nankana Sahib.

[18] However, the anniversary of Nanak's birth—the Gurpurab (gur + purab, 'celebration')—subsequently came to be celebrated on the full moon day of the Kattak month in November.

[24] Gurbilas Patashahi 6 written 1718[25] attributed to Bhai Mani Singh says Guru Nanak was born on the full moon of Katak.

[19] Kesar Singh Chibber’s Bansavalinama Dasan Patashahia Ka meaning genealogy of the ten emperors, written in 1769,[26] says Guru Nanak was born on the full moon of Katak as well.

[27] According to Max Arthur Macauliffe (1909), a Hindu festival held in the 19th century on Kartik Purnima in Amritsar attracted a large number of Sikhs.

[28] Macauliffe also notes that Vaisakh (March–April) already saw a number of important festivals—such as Holi, Rama Navami, and Vaisakhi—therefore people would be busy in agricultural activities after the harvest festival of Baisakhi.

Therefore, holding Nanak's birth anniversary celebrations immediately after Vaisakhi would have resulted in thin attendance, and therefore, smaller donations for the Sikh shrines.

On the other hand, by the Kattak full moon day, the major Hindu festival of Diwali was already over, and the peasants—who had surplus cash from crop sales—were able to donate generously.

[29] Nanak's parents, father Kalyan Chand Das Bedi (commonly shortened to Mehta Kalu[note 1][30]) and mother Mata Tripta,[31] were both Hindu Khatris and employed as merchants.

[citation needed] As a young man,[i] Nanak married Sulakhani, daughter of Mūl Chand (aka Mula)[ii][iii] and Chando Raṇi.

By the time of his death, Nanak had acquired several followers in the Punjab region, although it is hard to estimate their number based on the extant historical evidence.

When the quarreling Hindus and Muslims tugged at the sheet covering his body, they found instead a heap of flowers—and so Nanak’s simple faith would, in course of time, flower into a religion, beset by its own contradictions and customary practices.

A verse authored by him states that he visited several places in "nau-khand" ('the nine regions of the earth'), presumably the major Hindu and Muslim pilgrimage centres.

[41] Some modern accounts state that he visited Tibet, most of South Asia, and Arabia, starting in 1496 at age 27, when he left his family for a thirty-year period.

[36][49][50] These claims include Nanak's visit to Mount Sumeru of Indian mythology, as well as Mecca, Baghdad, Achal Batala, and Multan, where he would debate religious ideas with opposing groups.

[53] The Baghdad inscription remains the basis of writing by Indian scholars that Guru Nanak journeyed in the Middle East, with some claiming he visited Jerusalem, Mecca, Vatican, Azerbaijan and Sudan.

[51] Such embellishments and insertion of new stories, according to Callewaert and Snell (1993), closely parallel claims of miracles by Islamic pirs found in Sufi tadhkirahs of the same era, giving reason to believe that these legends may have been written in a competition.

Other direct and indirect borrowings in the Sikh janamsakhis relating to legends around his journeys are from Hindu epics and puranas, and Buddhist Jataka stories.

[52][59][60] The earliest biographical sources on Nanak's life recognised today are the janamsakhis ('birth stories'), which recount the circumstances of his birth in extended detail.

[61] The first, according to Cole and Sambhi (1995, 1997), based on the hagiographical Janamsakhis,[62] states that Nanak's teachings and Sikhism were revelations from God, and not a social protest movement, nor an attempt to reconcile Hinduism and Islam in the 15th century.

Rather, they include all Sikh Gurus, as well as the words of men and women from Nanak's past, present, and future, who possess divine knowledge intuitively through meditation.

[69] The Adi Granth and successive Sikh Gurus repeatedly emphasised, suggests Mandair (2013), that Sikhism is "not about hearing voices from God, but it is about changing the nature of the human mind, and anyone can achieve direct experience and spiritual perfection at any time.

"[70] The goal of man, taught the Sikh Gurus, is to end all dualities of "self and other, I and not-I," attaining the "attendant balance of separation-fusion, self-other, action-inaction, attachment-detachment, in the course of daily life.

[75][76] The fundamental beliefs of Sikhism, articulated in the sacred scripture Guru Granth Sahib, include faith and meditation on the name of the one creator; unity of all humankind; engaging in selfless service, striving for social justice for the benefit and prosperity of all; and honest conduct and livelihood while living a householder's life.

[80] Many Sikhs believe that Nanak's message was divinely revealed, as his own words in Guru Granth Sahib state that his teachings are as he has received them from the Creator Himself.

[81][failed verification] Many modern historians give weight to his teachings' linkage with the pre-existing bhakti,[82] sant,[v] and wali of Hindu/Islamic tradition.

[89][90] Trilochan Singh claims that, for centuries, Tibetans have been making pilgrimages to the Golden Temple shrine in Amritsar to pay homage to Guru Nanak's memory.