The election of Narendra Modi and his Bharatiya Janata Party, or the B.J.P., in 2014 led to renewed efforts to rewrite Indian history so as to legitimize Hindu nationalist ideology. These efforts had begun when the B.J.P. first governed India between 1999 and 2004.

Under Mr. Modi’s government and various state governments run by his party, the attempts to change history have taken many more forms, such as deleting chapters or passages from public school textbooks that contradicted their ideology, while adding their own make-believe versions of the past.

They have peddled myths and stereotypes through pliant media networks — and have been teaching these versions as history in schools run by the Rashtriya Swayemsevak Sangh, the parent body of Mr. Modi’s party, which he served as an outreach worker and organizer for numerous years.

Why is history so important to the Hindu nationalists?

Nationalists are known to construct an acceptable history to identify those they claim constitute the nation; extreme nationalists require their own particular version of the past to legitimize their actions in the present. Rewriting Indian history and teaching their version of it is crucial to justifying the ideology of Hindu nationalists.