I will get even further back. Islam enslaved ancient Persia. The Iranians would have been much more productive culturally if the Arabs hadn't converted them to this religion. Imagine a Persia, largely Aryan in its eseence, and the way it could have interacted with Europe. This exchange unfortunately never took place. The recent freaks who took over few decades ago additionally prevented Iran from becoming what it's meant to be - an open country ready to manifest its full potential free of religious fanaticism.