Udham Singh was an Indian revolutionary, best known for assassinating Michael O'Dwyer in March 1940 in what has been described as an avenging of the Jallianwalla Bagh Massacre. Singh changed his name to Ram Mohammad Singh Azad, symbolising the equality of all faith & of the three major religions of India: Hinduism, Islam and Sikhism. Singh is considered one of the best-known revolutionaries of the Indian independence struggle; he is also sometimes referred to as Shaheed-i-Azam Sardar Udham Singh. Bhagat Singh and Singh along with Chandrasekhar Azad, Rajguru and Sukhdev, were among the most famous revolutionaries in the first half of 20th-century India. For their actions, the British government labelled these men as "India's earliest Marxists".