“…In order to build the Sultanate of Yogyakarta as a way to resume Islamic civilization of Mataram Sultanate in the land of Mentaok, Hamengkubuwana I asked his brother, BPH Sandiyo to contribute to this development, because BPH Sandiyo was believed to have profound religious understanding of Islam and was still the son of Amangkurat IV the last ruler of Mataram Kartasura. The focus of this study was on the contribution of BPH Sandiyo in developing Islamic civilization, marking its difference from the previous studies of similar topics, such as a study conducted by Peter Carey, which concerned on the Giyanti Agreement and the Java War (Carey, 1986), a study by E. Setyowati focusing on the Pathok Negoro Mosque as a territorial defense area of the Mataram Sultanate of Java (Setyowati et al, 2018), a study by Yuli, which explained the role of Islamic boarding schools in building Muslim settlements (Yuli, 2020), or a study by Masdar Hilmy, which explained and focused on the existence of Islam in local communities (Hilmy, 2000). This study particularly addressed the contribution of BPH Sandiyo Putera Amangkurat IV in the Development of Islamic Civilization in the Yogyakarta Sultanate in the 18-19th century AD.…”