Mata Bhirai, the maternal grandmother of Guru Nanak, was married to Baba Rama of the village of Chahal, near Lahore. They has two children - a son called Baba Krishna and a daughter called Mata Tripta, who was destined to become Nanak's mother.
When Mata Tripta was married to Mahita Kalu, as was the custom then, she move to the residence of her husband which was Rai Bhoe Ki Talvandi (near Lahore). She moved to the present-day Nankana Sahib, which is the modern name of Rai Bhoe Ki Talvandi. It was in Nankana Sahib that Guru Nanak was born; the founder of the Sikh faith.
1. Santokh Singh, Bhai, Sri Gur Pratap Suraj Granth. Amritsar, 1926-37