The Indo-Aryan migrations were the migrations into the Indian subcontinent of Indo-Aryan peoples, an ethnolinguistic group that spoke Indo-Aryan languages, the predominant languages of today's North India, Pakistan, Nepal, Bangladesh, Sri Lanka and the Maldives. Indo-Aryan population movements into the region from Central Asia are considered to have started after 2000 BCE, as a slow diffusion during the Late Harappan period, which led to a language shift in the northern Indian subcontinent. Several hundred years later, the Iranian languages were brought into the Iranian plateau by the Iranians, who were closely related to the Indo-Aryans. The Proto-Indo-Iranian culture, which gave rise to the Indo-Aryans and Iranians, developed on the Central Asian steppes north of the Caspian Sea as the Sintashta culture (2050–1800 BCE) in present-day Russia and Kazakhstan, and developed further as the Andronovo culture (2000–1450 BCE). The Indo-Aryans split off sometime between 2000 BCE and 1600 BCE from the Indo-Iranians, and migrated southwards to the Bactria–Margiana culture (BMAC), from which they borrowed some of their distinctive religious beliefs and practices. From the BMAC, the Indo-Aryans migrated into northern Syria and, possibly in multiple waves, into the Punjab (northern Pakistan and India), while the Iranians could have reached western Iran before 1300 BCE, both bringing with them the Indo-Iranian languages. Migration by an Indo-European people was first hypothesized in the late 18th century, following the discovery of the Indo-European language family, when similarities between western and Indian languages had been noted. Given these similarities, a single source or origin was proposed, which was diffused by migrations from some original homeland. This linguistic argument of this theory is supported by archaeological, anthropological, genetic, literary and ecological research. Genetic research reveals that those migrations form part of a complex genetic puzzle on the origin and spread of the various components of the Indian population. Literary research reveals similarities between various, geographically distinct, Indo-Aryan historical cultures. Ecological studies reveal that in the second millennium BCE widespread aridization led to water shortages and ecological changes in both the Eurasian steppes and the Indian subcontinent, causing the collapse of sedentary urban cultures in south central Asia, Afghanistan, Iran, and India, and triggering large-scale migrations, resulting in the merger of migrating peoples with the post-urban cultures. The Indo-Aryan migrations started sometime in the period from approximately 2000 to 1600 BCE, after the invention of the war chariot, and also brought Indo-Aryan languages into the Levant and