Throughout the history of the Indian subcontinent from the 7th century to 13th century had been frequently subject to invasion from the North-West by Central nomadic tribes and the Persian Empire. With the fall of the Sassanids and the arrival of the Caliphates, these regions were integrated into Muslim dynasties of Central Asian Heritage ; initially Turkic people and later Mongol and Turco-Mongol people.Unlike earlier conquerors who assimilated into prevalent social system, Muslim conquerors retained their Islamic Identity and created legal and administrative systems that challenged and destroyed existing systems of social conduct, culture, religious practices, lifestyle and ethics.
It took several centuries for Islam to spread across India to forcibly convert to Islam through Jizya and Dhimmitude favoring Muslim citizens, and threat of naked forces or by intermarriage conversions, economic integration and through the influence if Sufi preachers.
Though the conversion came from Budhists and the en masse conversions of 'lower' castes for social liberation and as a rejection of the oppressive existent caste structures, conversion of Islam was directed not only for liberation of downtrodden people but also for global political domination.
