Baba Buddha Sahib ji served 6 Sikh Gurus and seen Future 7th Sikh Guru, Guru Har Rai Sahib Ji.
Baba Buddha Ji was the First Head Granthi of Sri Harmandir Sahib Ji. Baba Ji did Seva in constructing Baoli Sahib(84 Steps) built by Guru Amar Das Ji in Goindwal, helped in building Sri Amritsar Sarovaar, helped built Sri Harmandir Sahib Ji and Sri Akal Takht Sahib Ji.
Also,he was the one who did the Ceremony of Passing the GurGaddi for 5 Sikh Gurus.
Baba Buddha ji (6 October 1506 – 8 September 1631), one of the most venerated, primal figures of early Sikhism, was born on 6 October 1506 at the village of Katthu Nangal, 18 km northeast of Amritsar.
After sometime the family settled down in Dhalla village not far away from river Ravi opposite Kartarpur. “Bura”, as he was originally named, was the only son of Bhai Suggha, a Hindu Jatt of Randhawa clan, and Mai Gauran, who was born into a Sandhu family.
Also referred to reverently as Baba Buddha Ji; Bhai Buddha occupies a unique position in Sikh history and in the hearts of all Sikhs. He applied the tilak of guruship to five Gurus, saw and had the vision of seven Gurus and remained in close association with the first six Sikh Gurus from 1521 to 1631 for over one hundred years.
He was the first “priest” (or Giani) of Harimandir Sahib, and laid the foundations of Dera Baba Nanak and most of the holy buildings at Amritsar. It was the greatness of Guru Nanak that the seva (service or task) of applying tilak was given to Baba Buddha ji, given the fact that he belonged to a so-called low caste.