In our Pakistan History classes which were really about history of Sub Continent before partition, we were taught that Sir Sayyid Ahmed Khan was the father of two nation theory as he was the one who presented this idea forward first.
Whether he was father of two nation theory or not, he surely comes across as the one who sowed the seed. I recently came across following two passages in his seminal “The Causes of Indian Revolt (1873 translation)”
[5.2] If these two castes formed distinct Regiments perhaps the Mahommadans would not have objected to the use of the new cartridges.
Government certainly did put the two antagonistic races into the same regiment, but constant intercourse had done its work and the two races in regiment had almost become one. It is but natural and to be expected, that a feeling of friendship and brotherhood must spring up between the men of a regiment, constantly brought together as they are. They consider themselves as one body, and thus it was that the difference which exists between Hindus and Mahommadans had, in these regiments, been almost entirely smoothed away.
[5.3] The employment of Hindus and Mahommadans in the same regiment.
If a portion of the regiment engaged in anything, all the rest joined. If separate regiments of Hindoos and separate regiments of Mahommadans had been raised, this feeling of brotherhood could not have arisen, and, in my opinion, the Muhammadan regiments would not have refused to receive the new cartridges.
One should understand that Sir Sayyid Ahmed Khan did not have any ulterior motive in mind. He was saddened by the harsh consequences for Muslims for collaborating with Hindus in the 1857 revolt. His purpose for dividing regiments along religious lines was to avoid circumstances wherein Indians of all religions feel united to rise up again against their colonial masters and then face much harsher punishments.
British took this lesson further (whether they picked this idea from Sir Sayyid Ahmed Khan’s above essay or it was their own ingenious thinking I cannot say at the moment) and divided future regiments along ethnic, racial and even sectarian lines and then used this fact to their own best advantage.
PS: Thanks to A. H. Amin for introducing me to these facts.