Similarities between Sanskrit and European languages (especially with Latin and Greek) was first noticed by a merchant Filippo Sassetti, who lived in Goa between 1583 and 1588 A.D.
Sir William Jones and many other scholars who were in the service of East India Company elaborated the language similarities (between European and Indian languages).
On the basis of the similarities, some scholars postulated that the ancestors of Indians and Europeans, must at one time, had lived in the same region and spoken the same language.
The scholars called this Indo-European language and their common homeland as the Indo-European homeland. This created a great divergence of opinion about the problem of identifying the original homeland of the Aryans, which was still a matter of debate.
A number of homelands (of Aryans) have been propounded, such as Steppe of central Asia, southern Russia, southern Europe, Germany, Chinese Turkistan, or even Mediterranean area like Palestine and Israel. Almost everywhere, the Vedic language and its literature were found (except India).
The Rig Veda is the oldest surviving records of the Aryans. It does not give any evidence (even a suspicion) of any migration of Aryans from any other area.
Max Muller assigned period between 1,200 or 1,000 B.C. for this event. Max Muller as a true Christian believed in Bible and according to Bible, the world was created on 23rd October 4,004 B.C. and thus Max Muller had the challenge to accommodate the entire human history within the 6,000 years.
The Aryans were originally inhabitants of India and did not come from outside as there is no archaeological or biological evidence, which could establish the arrival of any new people from outside between 5,000 B.C. and 800 B.C.
The skeletal remains found from various Harappan sites resemble the skeletons of the modern population of the same geographical area.
A careful consideration of the evidence of the Rig Veda will lead to the conclusion that references it contains about people and their civilization may be taken to refer to the Harappan civilization.
The Discovery of Boghaz-Koi inscription (of 14th century B.C.) mentioned Rig Vedic deities that the Rig Veda existed earlier and the culture migrated from India to Asia Minor in that early age.
The time period of the Rig Veda in its final form should be placed not later than about 3,000 B.C.
The geographical distribution of the Harappan sites can be seen in the light of Rig Vedic geography as well.
The geographical features, mentioned in the Rig Veda, confirms the extension of Vedic Civilization from Afghanistan in the north to Gujarat in the south, Ganga in the east to Kubha (Kabul) in the west.
The Rig Vedic culture was flourished in the area around the Saraswati river and its tributaries; more than 80% of the Harappan settlements are found around the Saraswati valley thus it was the main area of Harappan civilization.
The animals known to the Indus people are also known to the Rig Veda, including sheep, dog, buffalo, bull, etc.
The animals hunted by the Rig Vedic people were antelopes, boars, buffalos (gaur), lions, and elephants most of them were also familiar to the Indus people.
A Terracotta Figurine of Horse found from Lothal. The horse was an important animal in the Vedic period. Horse bones and terracotta figurines have been found at some Harappan sites as well.
Some of the religious practices of the Harappan people like worship of Pipal trees, bull, Siva-lingas are still followed by the modern Hindus.
Some terracotta figurines of women found at Nausharo still have vermillion in their hair-parting. Vermillion in the Hair Parting is the most precious and sacred symbol of married Hindu women even today.
A terracotta tablet from Harappa depicts the scene of Mahisa sacrifice, reminding us of Mahisasuramardini.
The Harappan people were aware of using ornaments like earrings, necklaces, bracelets, anklets, garlands, and jewels.
Rig Veda mentions the use of gold and ayas (copper). Ayas was used in making of vessels.
The above-discussed similarities found between the Rig Vedic and Harappan civilization have led to the conclusion that the Harappan civilization is the same as the Vedic civilization and the Aryans did not come to India from outside.