"More than 4,000 years ago, the Harappa culture thrived in the Indus River Valley of what is now modern Pakistan and northwestern India, where they built sophisticated cities, invented sewage systems that predated ancient Rome's, and engaged in long-distance trade with settlements in Mesopotamia. Yet by 1800 BCE, this advanced culture had abandoned their cities, moving instead to smaller villages in the Himalayan foothills. A new study from the Woods Hole Oceanographic Institution (WHOI) found evidence that climate change likely drove the Harappans to resettle far away from the floodplains of the Indus." Source: Science Daily.
Note: The climate change in this case (~2500 BC) involved "a shift in temperatures and weather patterns over the Indus valley [which] caused summer monsoon rains to gradually dry up, making agriculture difficult or impossible near Harappan cities."
There was a big market in Rome for luxury goods from India and the East, but overland trade and travel to India was obstructed by the Arabs until Augustus came along. According to the Oxford Classical Dictionary (OCD 3rd ed. revised), "the Arab obstruction was removed by the great appetite of Rome for eastern luxuries in the prosperous days of Augustus, and by the discovery of open-sea routes from Aden to India. In the 1st cent. BC, or soon after, observation of the monsoon encouraged mid-ocean routes leading to various points on the western coast [of India] where settlements were subsequently established."
Roman trade with India was extensive. "In Augustus' day 120 ships sailed to India every year, and under his early successors the drain on Roman money to pay for Indian imports caused occasional anxiety..." (OCD) "...The principle imports to Rome were perfumes, spices (especially pepper), gems, ivory, pearls, Indian textiles, and Chinese silk."
The main trade was apparently with the Pandya kingdoms on the west coast of India. Evidence for this trade is still being uncovered today. For example, in 2015, The Hindu reported that "an excavation in Keezhadi, Sivaganga district, has thrown up a wealth of information on the flourishing Pandya trade with the west." The excavation can be viewed in this June 2016 video (no English version available).
The whole area of Roman contacts with India is difficult to research because of the language barrier. The next video's a good example. The slides are fantastic, but the speaker's hard to understand and the closed-captions are a joke.
"The Periplus Maris Erythraei (or ‘Voyage around the Erythraean Sea’ [the modern Red Sea]) is an anonymous work from around the middle of the first century CE written by a Greek speaking Egyptian merchant." (Source: Washington University) The document describes "the maritime trade-routes following the north-south axis from Egypt down the coast of East Africa as far as modern day Tanzania" and "the routes of the east-west axis running from Egypt, around the Arabian Peninsula and past the Persian Gulf on the west coast of India." The complete translation of this fascinating resource on the ancient sea trade can be found here. A detailed map of the Erythraean Sea in the 1st Century can be found here.
The Ajanta caves, also located in Maharashtra, are made up of "about 30 rock-cut, Buddhist cave monuments which date from the 2nd century BCE to about 480 or 650 CE," according to Wikipedia. "The caves include paintings and sculptures described by the government Archaeological Survey of India as 'the finest surviving examples of Indian art, particularly paintings which are masterpieces of Buddhist religious art, with figures of the Buddha and depictions of the Jataka tales."
The astronomical alignments and fantastic architecture of these cave temples have attracted the attention of the ancient-aliens crowd. (See next video.) Despite the evidence found all over the world, these researchers have never been able to accept the idea that ancient people were a lot more advanced than commonly believed. Confronted with a Stonehenge or a Hindu temple carved out of solid rock, they automatically assume that alien technology must have been involved. Still, if you can filter out the ET stuff, some of these documentaries are well worth watching.
"Hippalus (Ancient Greek: ππαλος) was a Greek navigator and merchant who probably lived in the 1st century BC. He is sometimes conjectured to have been the captain of the Greek explorer Eudoxus of Cyzicus' ship." Source: Wikipedia.
"The writer of the Periplus of the Erythraean Sea credited Hippalus with discovering the direct route from the Red Sea to India over the Indian Ocean by plotting the scheme of the sea and the correct location of the trade ports along the Indian coast."
According to the Oxford Classical Dictionary (OCD, 3rd ed. revised), Hippalus was "the merchant discoverer, in the Augustan or Tiberian age (1), of new ways of navigating the Arabian Sea; specifically the possibility of using the (very violent: his ships must have been substantial) SW monsoon to make deep-sea voyages from the south coast of Arabia to the NW coast of India, and the SE monsoon (a gentler wind) for the journey back to the mouth of the Red Sea..."
(1) Augustus ruled from around 27 BC - 14 AD, Tiberius from 14 - 37 AD.
The Romans had extensive trade, both by land and water, with India and the East as well as parts of eastern Africa along the coast of the Red Sea. Roman trading stations have been discovered on the coasts of India. For example:
"On the south-east or Coromandel Coast of India, about two miles (3.2km) south of the former French enclave of Pondicherry, there is a tract on the east known locally as Arikamedu, near the village of Virampattanam. After 1937 it was gradually revealed as an Indo-Roman trading station." Source: Ancient Origins.
"It appeared that the port began to rise about the end of the last century BCE, and reached its apogee in about 50 CE and later. The Roman remains included, for example, amphorae (wine-jars), Roman glass, Roman lamps, gems, etc. Moreover, the archaeological site revealed that the port city was used as a small ship-building or ship-repairing yard."
"On the shores of the Bay of Bengal, bathed in the rays of the rising sun, the [13th cent. Hindu] temple at Konarak [aka Konark] is a monumental representation of the sun god Surya's chariot; its 24 wheels are decorated with symbolic designs and it is led by a team of six horses. Built in the 13th century, it is one of India's most famous Brahman sanctuaries." Source: UNESCO World Heritage List.
According to Myoksha, a provider of pilgrimage tours and temple guides in India, "Konark Temple was referred to as 'Black Pagoda' by European travelers sailing the shores of the Arabian sea. It was so called maybe because of its dark colour due to continuous plastering and subsequent blackening of the surface over many centuries as mentioned by S.P Gupta in his book 'Temples in India'. It may also be that some European scholars believed that the exceptionally frank eroticism [next video] of many of the Konark sculptures has given it the name 'Black Pagoda'."
"The Sun Temple at Konarak was built in about 1250 AD by the East Ganga king Narasimhadeva, It is thought he built the temple to commemorate military successes against Muslim invaders." Source: Sacred Destinations.
"According to local legend, the temple has a great aura of power that comes from two very powerful magnets said to have been built into the tower - magnets that allowed the king's throne to hover in mid-air."
This magnetic aura could also be the reason for the name "Black Pagoda:"
"European mariners sailing off the coast used the temple's tower for navigation, but dubbed it the Black Pagoda for the frequent shipwrecks that occurred along the coast. They attributed the disasters to the legendary magnets' effect on the tidal pattern." (Sacred Destinations)
This is a magnificent temple, but King Narasimhadeva should be especially remembered for the fact that he "defeated the Muslim forces of Bengal who were constantly posing a threat to the Eastern Ganga dynasty's rule over Odisha [ancient Utkala], and because he was "one the few rulers in India who took the offensive against the Islamic expansion over India..." (Wikipedia)
Narasimhadeva should receive the same respect that we give to Charles Martel in the West.
"A new paper authored by 92 scientists from around the globe that was posted online this weekend could settle some major questions about the subcontinent’s history and what that means for various theories of Indian civilisation. The paper, titled 'The Genomic Formation of South and Central Asia' [PDF]which still has to go through peer review [emphasis added], uses genetics to examine the ancestry of ancient inhabitants of the subcontinent." Source: Scroll.in.
Note: There are several different variations of the Aryan or Indo-Aryan Migration Theory, but the basic idea is that the Aryans -- "the Indic people of the Vedic period [~1500 - 600 BC] in India" [Wikipedia] -- originally migrated into northern India from Central Asia around 1500 BC. According to the theory that I'm most familiar with, the Aryans wrote the Vedas and introduced Sanskrit and the caste system to India.
"Aryan" is a word the Indic people of the time used to refer to themselves. Some experts call them "Indo-Aryans" or "Indo-Iranians" or "proto-Indo-Europeans," depending on where the experts think they originated. Technically, "Aryan" is both a linguistic and an ethnic term:
There are two other general theories, both of which seem to have been discredited. According to the Aryan Invasion Theory, proposed by the British archaeologist Mortimer Wheeler, the Aryans invaded India and conquered the Indus Valley Civilization, but this was apparently refuted by new archaeological evidence. The other model, the Indigenous Aryans or Out of India Theory, which argues that the Indo-Aryans originated in India and then migrated into South Asia, has apparently been rejected for linguistic reasons.
That leaves the migration theory. Complicated by modern identity politics and the history of British colonialism in India, the theory has always been highly controversial, but this new study argues that "some sort of migration did indeed take place into India and that the Indus Valley civilisation is key to all South Asian populations." If I understand it right, that means that the migrants were related in some ways to the "Iranian agriculturists and South Asian hunter-gatherers or Ancient Ancestral South Indians" already living in the Indus Valley.
"The Vedic Age is the 'heroic age' of ancient Indian civilization. It is also the formative period when the basic foundations of Indian civilization were laid down. These include the emergence of early Hinduism as the foundational religion of India, and the social/religious phenomenon known as caste." Source: Time Maps.
This period of India’s history lasted from around 1500 BCE through to 500 BCE; that is, from the early days of the Aryan migration into north-west India through to the age of the Buddha."
"The Indus Valley civilization of ancient India was one of the earliest civilizations in world history. It was located in the north-western region of the Indian subcontinent, and its rise and fall form the first great chapter in the history of ancient India." Source: Time Maps.
"The Indus Valley is contemporary with the civilizations of Mesopotamia and Ancient Egypt. The civilization is famous for its large and well-planned cities. Over 1,052 cities and settlements have been found. Most of these are small, but amongst them are some of the largest cities of their time, especially Harappa and Mohenjo-daro."