Fossil remains of homo erectus, an ancestor of modern man (homo sapiens), have been found in the Solo and Brantas river valleys in Central Java. These fossils, known as Java Man, are estimated to be about 1.8 million years old; however, few traces of human life from the more recent Paleolithic and Mesolithic times (Old and Middle Stone ages) have been excavated. Some crude stone implements, such as a rectangular ax, and rock paintings in caves of the eastern islands have been found.Throughout history the peoples of Southeast Asia migrated extensively, giving the Indonesian archipelago a mix of more than 100 ethnicities and languages. Within this mix there has been a wide cultural gap between the coastal peoples, who probably developed irrigated wet-rice cultivation (sawah) about 2,000 years ago, and the inland peoples, who depended on shifting, slash-and-burn agriculture (ladang) until recently. The coastal regions probably developed sawah because irrigation was easier to develop near the coast and because the larger coastal populations made ladang difficult. Later, coastal peoples developed differently from inland peoples because the former were more exposed to outside influences. In time, three distinct types of Indonesian societies evolved. On the coast were the trade-oriented, deeply Islamic coastal peoples. Hindu-influenced, wet-rice cultivators developed further inland. Still further inland, typically in remote mountainous regions, were tribal groups who practiced shifting cultivation and indigenous religious beliefs.
Trade between Indonesia and India’s Bay of Bengal most likely began in the 1st and 2nd century ad. Although most historians no longer believe earlier theories that Indians conquered parts of Indonesia or settled it extensively, Indian culture exerted a powerful influence on the states that developed in the archipelago. Direct communication with China probably began between the 3rd and 5th century, as Indonesia exported cloves, tree resins, and camphor. In the early 5th century Faxian, a Chinese Buddhist pilgrim, and the princely monk Gunavarman from Kashmīr each wrote of direct voyages between western Indonesia and China.
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