Khalsa (ਖ਼ਾਲਸਾ, ˈkhaːlsaː, to be pure) refers to both a community that considers Sikhism as its faith, as well as a special group of initiated Sikhs. The Khalsa tradition was initiated in 1699 by the Tenth Guru of Sikhism, Guru Gobind Singh. Its formation was a key event in the history of Sikhism. The founding of Khalsa is celebrated by Sikhs during the festival of Vaisakhi.
Guru Gobind Singh started the Khalsa tradition after his father, Guru Tegh Bahadur, was beheaded during the Islamic sharia rule of the Mughal Emperor Aurangzeb. Guru Gobind Singh created and initiated the Khalsa as a warrior with a duty to protect the innocent from religious persecution. The founding of the Khalsa started a new phase in the Sikh tradition. It formulated an initiation ceremony (amrit sanskar, nectar ceremony) and rules of conduct for the Khalsa warriors. It created a new institution for the temporal leadership of the Sikhs, replacing the earlier masand system. Additionally, the Khalsa provided a political and religious vision for the Sikh community.
Upon initiation, a Khalsa Sikh is given the titles of Singh (male) meaning "lion" and Kaur (female) meaning "princess". The rules of life, include a behavioral code called Rahit. Some rules are no tobacco, no intoxicants, no adultery, no Kutha meat, no modification of hair on the body, and a dress code (Five Ks).
"Khalsa", is derived from the Arabic word "Khalis" which means "to be pure, to be clear, to be free from, to be sincere, to be true, to be straight, to be solid".
Sikhism emerged in the northwestern part of Indian subcontinent (now parts of Pakistan and India). During the Mughal empire rule, according to professor Eleanor Nesbitt, Khalsa originally meant the land that was possessed directly by the emperor, which was different from jagir land granted to lords in exchange for a promise of loyalty and annual tribute to the emperor.
Prior to Guru Gobind Singh, the religious organization was organized through the masands or agents.