Short answers, pulled from the story.
Islam first reached India through Arab seafarers trading along the Malabar and Gujarat coasts shortly after the religion emerged in the Arabian Peninsula. Historians place the first Muslim travellers on the Indian coast as early as 630 CE. The Cheraman Juma Mosque in Kerala, thought to have been built in 629 CE, is among the oldest mosques in the country.
According to the 2011 census, approximately 172.2 million people in India identified as Muslim, making up 14.2 percent of the total population. India holds the third-largest Muslim population in the world. The Pew Research Center projects the figure will reach 311 million by 2050.
Muhammad bin Qasim, at the age of 17, was the first Muslim general to invade the Indian subcontinent, reaching Sindh in 672 CE. The Delhi Sultanate, which later became the dominant Muslim political power in North India, was established in 1206 by successors of the Ghurid dynasty.
After the partition of British India in 1947, roughly two-thirds of the subcontinent's Muslims ended up in Pakistan while one-third remained in India. The 1951 census recorded 7,226,000 Muslims who had moved to Pakistan from India. The Muslim share of India's population fell from 13.3 percent in 1941 to 9.8 percent in 1951 as a result.
Over 85 percent of Indian Muslims are Sunni, with the Barelvi movement holding the largest following; the Deobandi movement is another significant Sunni tendency. About 13 percent or more are Shia. Smaller communities include the Bohra Shia, the Khojas, the Ahmadiyya, and Quranists.
Many Muslim leaders participated directly in the struggle against British rule. Khan Abdul Gaffar Khan, known as the Frontier Gandhi, spent 45 of his 95 years in jail. Syed Rahmat Shah was hanged in 1915 for his role in the Ghadar Mutiny. Muhammad Ali Jinnah was a member of the Indian National Congress until 1920.