The Hindu Mahasabha was an important part of the early Hindu Nationalist movement. Initially a group within Congress, it became a full-fledged party under the leadership of V. D. Savarkar in the late 1930s. As president of the Hindu Mahasabha, Savarkar advanced the slogan "Hinduize all Politics and Militarize Hindudom".
In modern times, the Hindu Mahasabha continues to exist as a group within the Sangh Parivar, advocating violence against Christians and Muslims, getting involved in moral policing crusades, and campaigning for the commemoration of Nathuram Godse.
References
• Hindu Nationalism: A Reader Edited by Christophe Jaffrelot, Princeton, 2007.
• Articles about the Hindu Mahasabha on The Wire and on Narendra Modi Facts.