Islam is the second-largest religion in South Asia, with more than 650 million Muslims living there, forming about one-third of the region's population.

Islam first spread along the coastal regions of the Indian subcontinent and Sri Lanka, almost as soon as it started in the Arabian Peninsula, as the Arab traders brought it to South Asia.

Native legends say that a group of Sahaba, under Malik Ibn Deenar, arrived on the Malabar Coast and preached Islam.

[25][26][27][28][23] The first incursion occurred through sea by Caliph Umar's governor of Bahrain, Usman ibn Abu al-Aas, who sent his brother Hakam ibn Abu al-Aas to raid and reconnoitre the Makran region[29] around 636 CE or 643 AD long before any Arab army reached the frontier of India by land.

The first Indian mosque is thought to have been built in 629 CE, purportedly at the behest of an unknown Chera dynasty ruler, during the lifetime of Muhammad (c. 571–632) in Kodungallur, in district of Thrissur, Kerala by Malik Bin Deenar.

Henry Rawlinson, in his book Ancient and Medieval History of India, claims the first Arab Muslims settled on the Indian coast in the last part of the 7th century.

[36] This fact is corroborated, by J. Sturrock in his South Kanara and Madras Districts Manuals,[37] and also by Haridas Bhattacharya in Cultural Heritage of India Vol.

According to Derryl N. Maclean, a link between Sindh and early partisans of Ali or proto-Shi'ites can be traced to Hakim ibn Jabalah al-Abdi, who traveled across Sind to Makran in the year 649AD and presented a report on the area to the Caliph.

[46] The Sufis did not preach egalitarianism, but played an important role in integrating agricultural settlements with the larger contemporary cultures.

Richard M. Eaton has described the significance of this in the context of West Punjab and East Bengal, the two main areas to develop Muslim majorities.

Improved transport services in the nineteenth century brought Muslim masses into contact with Mecca, which facilitated reformist movements stressing Quranic literalism and making people aware of the differences between Islamic commands and their actual practices.

Founded by Shah Mir around 1320, this sultanate ruled the Kashmir Valley until it was gradually incorporated into the expanding Mughal Empire by the late 16th century.