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. South Asia has the largest population of Muslims in the world, with about one-third of all Muslims living here.[17][18] Islam is the dominant religion in half of the South Asian countries (Pakistan, Maldives, Bangladesh and Afghanistan). It is the second largest religion in India and third largest in Sri Lanka and Nepal.
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. Al-Hakim ibn Jabalah al-Abdi, who attacked Makran in the year 649 AD, was an early partisan of Ali ibn Abu Talib.[30] During the caliphate of Ali, many HinduJats of Sindh had come under the influence of Shi'ism[31] and some even participated in the Battle of Camel and died fighting for Ali.[30] According to popular tradition, Islam was brought to Lakshadweep islands, situated just to the west of Malabar Coast, by Ubaidullah in 661 CE. After the Rashidun Caliphate, Muslim dynasties came to power.[32][33] Since the 1947 partition of India, South Asia has been largely governed by modern states,[34][35] with Pakistan, which later split into Pakistan and Bangladesh in 1971, emerging as the primary Islamic country in the region.
^Prof.Mehboob Desai,Masjit during the time of Prophet Nabi Muhammed Sale Allahu Alayhi Wasalam,Divy Bhasakar,Gujarati News Paper, Thursday, column 'Rahe Roshan',24 May,page 4
^Jo Van Steenbergen (2020). "2.1". A History of the Islamic World, 600–1800: Empire, Dynastic Formations, and Heterogeneities in Pre-Modern Islamic West-Asia. Routledge. ISBN978-1000093070.
^Jalal, Ayesha; Bose, Sugata (1998), Modern South Asia: History, Culture, Political Economy (1st ed.), Sang-e-Meel Publications
^Talbot, Ian (2016), A History of Modern South Asia: Politics, States, Diasporas, Yale University Press, ISBN 978-0-300-21659-2