Kalidas Nag (; 16 January 1892 â 9 November 1966) was an Indian historian, writer and parliamentarian. He was nominated to the Rajya Sabha in 1952 and served till 1954.
Kalidas Nag was born to Babu Matilal Nag in Calcutta. He married Shrimati Santa Devi, daughter of Ramananda Chatterjee. Together they had three daughters.
After graduating in history from the Scottish Church College, he earned a postgraduate degree from the University of Calcutta, and a doctorate from the University of Paris. A prolific author, he taught history at the Scottish Church College and University of Calcutta, and was nominated as an Officer dâ Academic by the Government of France. He served as the principal of Mahinda College in Galle, Ceylon from 1919 to 1920. In the 1920s he was a supporter of the French contribution to Tagore's university project at Santiniketan (north of Calcutta). He later edited several books on Indian culture.
Nag had major correspondence and intellectual relationships with two formidable European intellectuals, Romain Rolland and Hermann Hesse. Nag had famously narrated the story of the life of the Buddha to Hesse at a conference, which became the basis for Hesse's novel Siddhartha.