Baba Sri Chand (1494-1629) was the eldest son of Guru Nanaak Dev ji. Sri Chand was a devoted Sikh and a saintly person, but unlike his father, he chose the life of an ascetic and renounciate yogi. After his father left this earthly plane, Baba Sri Chand stayed in Dera Baba Nanak and maintained Guru Nanaak Dev's temple. Here he established the Udasis sect who traveled far and wide to spread the Word of Nanaak. Many years passed, with Siri Chand keeping company with his own disciples. Sri Chand heard about the beautiful new city of Ram Das Pur, and the compassion and humility of the Fourth Guru, Guru Ram Das ji. Curious, he set out to meet him. When Baba Sri Chand met Guru Ram Das, he commented that Guru Ram Das had the longest beard he had ever seen. Guru Ram Das, in an expression of honor to the House of Nanaak, said, "It is only long in order to wipe the feet of the saints". Guru Ram Das bent down to do so, and Baba Sri Chand pulled his feet back in surprise. Guru Ram Dasís humility touched Siri Chand deeply and he declared to everyone, "This is truly the Light of Guru Nanaak." From that time forward, Baba Sri Chand maintained close contact with the Sikh sangat. Upon Baba Sri Chand's death at the age of 135, the son of Guru Hargobind, Baba Gurditta was appointed his successor as head of the Udasis. They received support and guidance from the Sikhs, and lived together all across the Punjab. The Udasis protected and maintained the historical Gurdwaras of Anandpur, Hazoor Sahib and Amritsar for over a hundred years after Guru Gobind Singh's death, during the time of great persecution of the Sikhs. During this time, they established schools of learning to keep alive the knowledge of Sikh history and Gurmukhi language.
From: The Encyclopaedia of Sikhism and McCauliffe