The Khalsa was founded at a specific moment rather than growing gradually: at Vaisakhi in 1699, at Anandpur, Guru Gobind Singh called for volunteers willing to give their lives, tested five men who came forward, the Panj Pyare or five beloved ones, and initiated them and then himself into a new order marked by five physical signs, the five Ks, that made initiated Sikhs visibly identifiable to each other and to anyone else.
The founding solved a problem the community faced repeatedly across the lifetimes of the Gurus, disputed claims to succession and authority by rival family members and pretenders, by building a corporate identity that did not depend on any one leader's person. That design became explicit at the end of Guru Gobind Singh's own life: before his death in 1708 he declared that there would be no further living Guru, and that the scripture, the Guru Granth Sahib, would thereafter be regarded as the eternal Guru, with the Khalsa Panth itself carrying forward the Gurus' continuing authority in the world. The order that had been founded to give the community a collective backbone during the Gurus' lifetimes became, by that declaration, the institution meant to carry Sikh authority forward permanently once no individual Guru would ever hold it again.