Madagascar and the East African coast. This is indicated by the existence of outriggers and oculi (eye ornament) on African boats. Moving eastward Around the year 929, the centre of the kingdom was shifted from Central Java to East Java by Mpu Sindok, who established the Isyana dynasty. The exact cause of the move is still uncertain. Historians have proposed various possible causes; from natural disaster, epidemic outbreak, politics and power struggle, to religious or economic motives. According to van Bemmelen's theory, which was supported by Prof. Boechari a severe eruption of Mount Merapi volcano probably has caused the move. Historians suggest that, some time during the reign of King Wawa of Mataram (924–929), Merapi volcano erupted and devastated the kingdom's capital in Mataram. The historic massive volcano eruption is popularly known as Pralaya Mataram (the debacle of Mataram). The evidence for this eruption can be seen in several temples that were virtually buried under Merapi's lahar and volcanic debris, such as the Sambisari, Morangan, Kedulan, Kadisoka and Kimpulan temples. Archeologist Agus Aris Munandar proposed a hypothesis, that the move was caused by a religious motives. He mentions that the incessant eruptions of Mount Merapi has caused the kingdom to move. Pointing out that in ancient Javanese beliefs, Merapi was considered as the Mahameru for the people in the ancient Mataram. According to Hindu teachings, the Mahameru peak symbolises the centre of the universe, the sacred realm where the gods live. Since their Mahameru in Central Java continued to erupt, they decided to move, but they still looked for another Mahameru. As East Java was still part of Mataram territory, it is possible that some of the people informed the Central Java kingdom that there was another Mahameru in the east. He suggests that the new sacred mountain was Mount Penanggungan in East Java, which resembles Mahameru. Another hypothesis proposed by N.J. Krom says that the demise was caused by an epidemic break-out, forcing people to seek a new place to live. On the other hand, B. Schrieke says the move was caused by economic reasons; the vigorous temple construction boom during the era of Shailendran kings has put a tremendous economic burden upon the peasant. People were suffering as they were forced to build grand temples by the kings, instead of working their farms. Slowly they moved to the east to avoid the kings' orders. A power struggle is