ardent temple construction projects was actually a religious-political tool to control the regional Rakai landlords, to prevent them from rebelling against the king. During this time, each of regional watak are ruled by Rakai landlords that nurturing their own dynasty. By appointing the Rakais' sima land to fund the construction and maintenance of a candi religious building, the Maharaja depriving the Rakais' ability to collect large sum of tax, that can be potentially misused to fund some army that might rose to challenge the Maharaja's authority. The Rakais might be willingly or reluctantly compliant to the king's will, for refusing to construct religious building might harm their reputation, and cast them not only as the enemy of the king, but also as the enemy of gods or Buddha. Art and Architecture Other than examining bas-reliefs carved on the temple's walls, the study of ancient Javanese society is also conducted through archaeological relics. The Wonoboyo hoard golden artefacts attest to the wealth, art, and culture as well as the aesthetic achievement of the Mataram Kingdom. The artefacts show the intricate artwork and technical mastery of the ancient Javanese goldsmith. The hoard was estimated to date from the reign of King Balitung. The treasure has been identified as belonging to a noble or a member of the royal family. The earliest temple in the Southern Central Java Mataram region was the Hindu Shivaist Gunung Wukir temple, linked to Canggal inscription (732 CE) built by King Sanjaya. Almost 50 years later the oldest Buddhist temple was built in Prambanan region, the Buddhist Kalasan temple, linked to Kalasan inscription (778 CE) and King Panangkaran. From this time, the kingdom saw exuberant temple construction projects, such as Sari, Manjusrigrha, Lumbung, Ngawen, Mendut, Pawon and peaked in the construction of Borobudur, the massive stone mandala, that took shape of a mountain temple pinnacled with stupas that completed c. 825 CE. The monumental Hindu temple of Prambanan in the vicinity of Yogyakarta—initially built during the reign of King Pikatan (838–850), and expanded continuously through the reign of Lokapala (850–890) to Balitung (899–911)—is a fine example of ancient Mataram art and architecture. The description of a grand temple compound dedicated for lord Shiva, and the public project to shift the course of the river near the temple (Opak river) to run straight along western wall of temple compound was also mentioned in Shivagrha inscription. The grand temple complex