I am too old now to continue to believe that the name Hindu was for the first time given to us as one involving abuse, contempt and reproach by our Mohammedan invaders. Rather, I believe that our fall and degradation helped the fall of the word also, and perhaps a peep into the philological history of the word might prove that all the bad meanings that are now assigned to the word in the Persian lexicon were of a comparatively later origin, and an outcome of the fall of the Hindu nation. Long before the Mohammedan invasion, and perhaps long before the advent of the Prophet of Islam, we were known to the people of other countries as Hindus. If so, what did this name signify? Was it a tribal distinction? I say, no, because the Hindus were of many tribes. Was it a racial name? I again say, no, because the Persians of Iran too, belonged to the same race. Was it then a religious designation? Yes, partly religious no doubt, but mainly national, and in evidence I can produce a number of quotations from the productions of early Greek historians and Mohammedan writers.
[See the full post at: A Study of Hindu Nationalism – Lala Lajpat Rai-1902]