The Nankana massacre took place in Nankana Sahib gurdwara on 20 February 1921, at that time a part of the British India but today in modern-day Pakistan. More than 260 Sikhs were killed, including children as young as seven, by the Udasi Custodian Mahant Narayan Das and his mercenaries. The event forms an important part of Sikh history. In political significance, it comes next only to Jallianwala Bagh massacre of April 1919. The saga constitutes the core of the Gurdwara Reform Movement started by the Sikhs in early twentieth century.