Fossilised remains of Homo erectus, popularly known as the "Java Man", dating back 1.7 million years were found along the banks of the Bengawan Solo River.
The island's exceptional fertility and rainfall allowed the development of wet-field rice cultivation, which required sophisticated levels of cooperation between villages. Out of these village alliances, small kingdoms developed. The chain of volcanic mountains and associated highlands running the length of Java kept its interior regions and peoples separate and relatively isolated. Before the advent of Islamic states and European colonialism, the rivers provided the main means of communication, although Java's many rivers are mostly short. Only the Brantas and Sala rivers could provide long-distance communication, and thus their valleys supported the centres of major kingdoms. A system of roads, permanent bridges and toll gates is thought to have been established in Java by at least the mid-seventeenth century. Local powers could disrupt the routes as could the wet season and road use was highly dependent on constant maintenance. Subsequently, communication between Java's population was difficult.
Hindu-Buddhist kingdoms era
The Taruma and Sunda kingdoms of western Java appeared in the fourth and seventh centuries respectively. However, the first major principality was the Medang Kingdom which was founded in central Java at the beginning of the eight century. Medang's religion centred on the Hindu god Shiva, and the kingdom produced some of Java's earliest Hindu temples on the Dieng Plateau. Around 8th century the Sailendra dynasty rose in Kedu Plain and become the patron of Mahayana Buddhism. This ancient kingdom built monuments such as 9th century Borobudur and Prambanan in central Java.
Around 10th century the centre of power shifted from central to eastern Java. The eastern Javanese kingdoms of Kediri, Singhasari and Majapahit were mainly dependent on rice agriculture, yet
