Baba Sri Chand
Sri Chand (1494–1629) was the eldest son of Guru Nanak Dev. Sri Chand had a reputation of saintliness, and was respected and liked by all.Bibi Nanaki Ji took Shri Chand and adopted him as her own son. This type of arrangement was a quite common and accepted custom at that time. Sri Chand was a renounciate yogi.
After his father, Guru Nanak left Nankana Sahib, Sri Chand stayed in Dera Baba Nanak and maintained Guru Nanak's temple. He later on established the Udasi order who travelled far and wide to spread the Word of Nanak.
When Guru Ram Das met Baba Sri Chand, the Baba commented that Guru Ram Das had the longest beard he had seen. Guru Ram Das replied, "It is to wipe the feet of the saints". Guru Ram Das bent down to do so, and Sri Chand pulled his feet back in surprise.
After Baba Sri Chand's death at the age of 135, the son of Guru Hargobind, Baba Gurditta became his successor as head of the Udasis. The Udasis protected and maintained the historical shrines of Anandpur, Hazoor Sahib and Amritsar for over a hundred years after Guru Gobind Singh's death. They established schools of learning to keep the Sikh tradition alive.
M A Macauliffe, The Sikh Religion, Its Gurus, Sacred Writings and Authors(1909)