Rowlatt's paternal great-grandfather, Sir Sidney Rowlatt, was a prominent judge on the King's Bench Division of the High Court of England and Wales. In 1918, he headed the controversial Rowlatt Committee to evaluate terrorism and seditious movements in British India, and drafted the repressive Rowlatt Act, which authorised stricter press censorship and the arrest and indefinite detention of suspects without due process. The passage of the Act in March 1919 ignited protests across the subcontinent and led directly to the Jallianwala Bagh massacre (also known as the Amritsar Massacre); it has been cited as a major factor in stimulating and expanding the Indian independence movement.