Guru Har Krishan Ji was five when he became Guru and seven when he died. He is called Bala Pritam, the child beloved.
Ram Rai contested the succession at the Mughal court and Aurangzeb summoned the boy to Delhi. He stayed at the house of Raja Jai Singh, which is now Gurdwara Bangla Sahib. He refused an audience with the emperor.
Delhi was in a smallpox epidemic. The tradition holds that he attended the sick and contracted the disease and died of it in 1664. The water of the tank at Bangla Sahib is taken by pilgrims for that reason.
Asked for a successor he said only Baba Bakala, meaning the next Guru was at the village of Bakala. Twenty-two claimants set themselves up there. The account of how the real one was found, by a trader named Makhan Shah Labana who had vowed five hundred gold coins in a storm at sea and offered two to each claimant until one asked for the rest, is the origin of the phrase Guru ladho re, the Guru is found.
That Guru was Tegh Bahadur Ji, a son of Guru Hargobind Sahib Ji who had been living quietly at Bakala for twenty years.
He became Guru at five and died at eight, which makes him the youngest and the shortest tenured of the ten.
He was summoned to Delhi by Aurangzeb, stayed at Raja Jai Singh's bungalow, and served the sick during an outbreak in the city before contracting it himself.
His last words are recorded as Baba Bakala, directing the sangat to look for his successor there. Gurdwara Bangla Sahib stands where the bungalow was.