Indonesia did not exist as yet during the Palaeocene period (70 million years BC), the Eocene period (30 million years BC), the Oligacene period (25 million years BC) and the Miocene period (12 million years BC). It is believed that Indonesia must have existed during the Pleitocene period (4 million years BC) when it was linked with the present Asian mainland. It was during this period that the Homonids made their first appearance and Java Man inhabited the part of the world now called Indonesia. Java Man, named Pithecanthropus Erectus by Eugence Dubois who found the fossils on the island of Java, must have been the first inhabitant of Indonesia.
When the sea level rose as the result of the melting ice north of Europe and the American continent, many islands emerged, including the Indonesian archipelago. It was also during this period (3000-500 BC) that Indonesia was inhabited by Sub Mongoloid migrants from Asia who later inter-married with the indigenous people. Later still (1000 BC) inter-marriage occured with Indo-Arians migrants from the south Asian sub-continent of India. The first indian migrants came primarily from Gujarat in Southeast India during the first Christian era.
The Caka period in Indonesia witnessed the introduction of the Sanskrit language and the Pallawa script by the Indian Prince Aji Caka (78 AD). The Devanagari script of the sanskrit language was also used, as shown in ancient stone and copper inscriptions (paracasthies) which have been unearthed. The language and script were adopted and called the Kawi language and included words and phrases derived from Javanese.
Early trade relations were established between South India and Indonesia. Sumatra was then named Swarna Dwipa of “the island of gold, ” Java was called Java Dwipa or “the Rice island,” and a Hindu kingdom of Crivijaya in Sumatra and Nalanda in South India were not comfirmed to religious and cultural exchanges. They later developed diplomatic relations, and even covered a wide range of trade. The influx of Indian settlers continued during the period from the first to the seventh century AD. Peacefully and gradually the Hindu religion spread throughout the archipelago. It was adopted by all layers of the people of Java, but limited to the upper classes on the other islands