Sultan Hamengkubuwono IX was the ruler of the Yogyakarta Sultanate in Indonesia from 1940 until his death in 1988. He played a significant role during the Indonesian National Revolution, supporting the country's struggle for independence from Dutch colonial rule. His leadership helped to establish Yogyakarta as a cultural and political center in Indonesia. In addition to his royal duties, Sultan Hamengkubuwono IX was also involved in politics. He served as a vice president of Indonesia from 1973 to 1978. His contributions to both the Yogyakarta Sultanate and the nation have made him a respected figure in Indonesian history.