Udham Singh (December 26, 1899 - July 31, 1940), born Sher Singh was a Sikh Punjabi Marxist and nationalist best known for assassinating Michael O'Dwyer in March 1940 in what has been described as an avengement of the Jallianwalla Bagh Massacre. Singh was also known as Ram Mohammed Singh Azad, symbolizing the unification of the three major religions of India: Hinduism, Islam and Sikhism. Singh Considered one of the best-known of the more extremist revolutionaries of the Indian freedom struggle, he is also sometimes referred to as Shaheed-i-Azam Sardar Udham Singh (the expression "Shaheed-i-Azam" means "king of martyrs"). Along with Bhagat Singh, Udham Singh is also believed to be one of the earliest Marxists/Bolsheviks in India. Whilst living in England in 1940, Singh shot dead Sir Michael O'Dwyer, who had been Governor of the Punjab during the Amritsar Massacre, when General Reginald Edward Harry Dyer's ordered British troops to fire on unarmed Indian protesters in Punjab, mostly Sikhs.