“Who Ruled India?” is an interesting question. The history of rule in India goes back to great antiquity, back and back to the days of the Mahabharata (emperors such as Yudhisthira and Pariksit Maharaja) and before that to the days of the Ramayana when Sri Ramacandra sat on the throne of Ayodhya.
There is a great misunderstanding in the secular and religious world and especially within the Abrahamic traditions, (Judaism, Islam and Christianity) on the question of Deity worship. The English word 'idol' is usually used when describing any worship that concentrates on likenesses of demons, gods, goddesses, Visnu or Krsna. The term 'idol' has a very bad connotation in the west and conjures up images of pagans, heathens and other wild uncultured persons ...
There is no such statement in the revealed scriptures [sastras] that Visnu/Krsna [God] reveals His teachings in many places simultaneously. When it is mentioned that religion is taught according to time, place and circumstances, then that is referring to bona-fide teachers of eternal religion like Sri Ramanujacarya and Sri Madhvacarya and not upstarts like Mohammed, Jesus or St. Paul.
Wasn't there perhaps sincerity in some of these religions at the time when they emerged? God is omnipresent and, after all, a man in the desert who had some desire to know truth would experience an aspect of God's beauty, power, love etc. He could feel that to be God and not yet know about Sri Krishna, due to his unfortunate karma of not being near a pure devotee. Does it mean that he has no realization just because he doesn't yet know about Krishna?
During a recent visit to Europe I had some informal discussions about religious conceptions with other Gaudiya Vaisnavas and I was surprised to hear some devotees speak about such groups as the Sufis, Whirling Dervishes, Jews, Christians, Catholics, Orthodox Christians and Muslims as being deeply 'surrendered' souls. Of course, generally speaking this may be true – but surrendered to what?