Guru Tegh Bahadur (1621-1675) was the youngest son of Guru Hargobind, born Tyag Mal and renamed, the tradition says, Tegh Bahadur, "brave of the sword", for his conduct in his father's battles. He then spent long years in seclusion and meditation at Bakala, and it was there that the community, following Guru Har Krishan's dying words, found him and set aside the pretenders who had claimed the office.
As Guru he founded the town of Anandpur (Chak Nanaki) in the Shivalik foothills, which would become the crucible of the later Khalsa, and he travelled very widely, through the Malwa, into the eastern Gangetic plain, Bengal and Assam, teaching and establishing congregations. It was at Patna, during these travels, that his son and successor, the future Guru Gobind Singh, was born.
His travels through Bengal and Assam in the 1660s built congregations, sangats, that endured long after his death and drew him into contact with Assamese and Bengali rulers; a local Assamese chronicle, the Ahom Buranji, is among the few contemporary non-Sikh sources to record his presence in the region. He returned west in 1670 to raise his son at Anandpur. His final journey, prompted by an appeal from Kashmiri Pandits resisting forced conversion under Aurangzeb's administration, ended in his execution at Delhi in 1675, on the emperor's order, for refusing to renounce his faith.