Mata Sahib Kaur Ji is called the mother of the Khalsa. At the amrit ceremony the sugar crystals put into the water are attributed to her, and every Sikh initiated since is formally her child, as Guru Gobind Singh Ji is the father.
That formula is recited at every amrit sanchar. It gives the Khalsa a single ritual parentage and cancels the lineage of birth, which in a caste society is the entire point of it.
She was from Rohtas in Jhelum district. She had no children. She was with the Guru at Anandpur and afterward, and he entrusted her with five weapons before he died at Nanded.
She lived at Delhi after 1708 and issued hukamnamas to the sangat. Several survive.
Gurdwara Mata Sundari at Delhi commemorates her and Mata Sundari Ji together.
Her authority after 1708 was exercised alongside Mata Sundari Ji's and the two are commemorated together, which is unusual. The tradition normally settles on a single figure and here it keeps both.
The tradition that she added patasas to the amrit being prepared is why her presence at the founding is remembered in that particular way. The account is that the sweetness was accepted as something the Khalsa would need alongside its steel.
She left Nanded after 1708 and lived at Delhi with Mata Sundari Ji. The hukamnamas issued from Delhi in that period are among the few documents of Sikh authority between 1708 and the rise of the misls.