Islam is the second-largest religion in India (after Hinduism - 80.5%), where Muslims number around 137 million (13.4%). India has the third-largest population of Muslims in the world after Indonesia and Pakistan.
Since its introduction to India, Islam has made religious, artistic, philosophical, culture, social and political contributions to Indian history, heritage and life. It has also been involved in many social, religious and political conflicts.
Contrary to general belief, Islam came to India long before Mughals. Trade relations between Arabia and Indian sub-continent are very ancient. Arabs used to visit the coast of Southern India, which was a link between the ports of South and South East Asia, even before Islam had been established in Arabia. As these traders became Muslim, Islam was slowly brought to South Asia. A number of local Indians living in the coastal areas (Kerala) were moved by the principles of Islam and got converted. The first Indian mosque was built in Kasargod during 642 A.D (22 Hizri). In the 8th century, the province of Sindh was conquered by Syrian Arabs led by Muhammad bin Qasim. Sindh became the easternmost province of the Umayyad Caliphate.
In the first half of the 10th century a Mahmud of Ghazni added the Punjab to the Ghaznavid Empire and conducted several raids deeper into mordern day India. A more successful invasion came at the end of the 12th century by the Muhammad of Ghor. This eventually led to the formation of the Delhi Sultanate.
Historian Will Durant wrote in The Story of Civilization (1972) that the Muslim conquest of India was "probably the bloodiest story in history." The number of people killed is estimated based on the Muslim chronicles and demographic calculations. K.S. Lal estimated in his book The Growth of Muslim Population in India that between 1000 CE and 1500 CE, the population of Hindus decreased by 80 million.
Islam in Modern India
Muslims in India post-Independence have had a mixed and sometimes turbulent history. The aftermath of the Partition of India in 1947 saw large scale sectarian strife and bloodshed throughout the nation. During partition, large populations of Muslims, including many who were rich and educated, left for Pakistan. Across the border, these immigrants or 'Muhajirs' have ever since played an important role in the development of Pakistan. The majority of Muslims in India are economically backward; however, like in all minorities, there are Muslims who have played a special role in all fields of the country's advancement. Still, Muslims have sometimes been the victims of religious fundamentalism. At the same time, Muslim fundamentalist groups also hold prominence in states like Jammu and Kashmir. There is an increasingly heated debate on whether what secularists in India classify as religious fundamentalism is only limited to the Hindu side in an attempt to protect the Muslim minority. The recent issue regarding the Ayodhya temple site shows that these problems, products of religious nationalism some 70 years ago, are hardly likely to go away in the near future.