It was because of Krishna Deva Raya, Orissa lost it's military edge over the muslim Afghan rulers of Bengal and eventually came under Mughal empire. When Orissa was was busy fighting the the muslim invaders on it's norther borders (around mid 1500 AD), Krishna Deva Raya attacked from south and forced Orissa to divide it's military resources which ultimately brought death and destruction and down fall to Orissa. This is a classic example of infighting between hindu rulers which ultimately helped the muslim invaders. Krishna Deva Raya may be a good ruler for his country men but he certainly is not a great ruler.
