My dear Karthik, as a Hindu I know all these facts and feel ashamed about this. Thats why Raja Rammohan Roy, Pandit Ishwarchandra Vidyasagar and Vivekananda are visionary. The Hindus accpet very well some parts of the dark periods. The thing is that let the majority Muslims also accept the dark periods of Muslim rule in India. Why are you talking un-necessary things?