History of Nankana Sahib
The town was once called Rai Bhoi Ki Talwandi. Guru Nanak was born here to Mehta Kalu and Mata Tripta, and the local landlord Rai Bular Bhatti, who became one of the Guru’s earliest devotees, later renamed it in his honour.
A first shrine on the birthplace is believed to have been raised in the 16th century by Baba Dharam Chand, the Guru’s grandson. The present Gurdwara Janam Asthan was built under Maharaja Ranjit Singh in the early 19th century.
The town is also remembered for the Nankana massacre of 20 February 1921, when 86 reformist Sikhs were killed in a confrontation with the mahant who then controlled the shrine. The episode became a turning point in the Gurdwara Reform Movement, and the jand tree and well associated with it are preserved at Janam Asthan. Today the gurdwaras are run by the Pakistan Sikh Gurdwara Parbandhak Committee (background on Wikipedia).