Umm, the Mughal, the Guptas? Also the pratiharas, rashtrakutas and palas collectively ruled over india too. The Delhi sultanate was pretty huge too, and so was

Umm, the Mughal, the Guptas? Also the pratiharas, rashtrakutas and palas collectively ruled over india too. The Delhi sultanate was pretty huge too, and so was the maratha empire. But being a single governance group isn't the point. Being culturally similar is what defines India. And it obviously is.