This thesis explores the phenomenon of Darul Islam (DI), a radical Islamist movement that emerged in Indonesia in the late 1940s and has been involved in bloody revolution since then. Drawing on ethnographic fieldwork and historical sources, this thesis examines the ideological, social, and political dimensions of DI, as well as its relation to other Islamist groups and the state. The thesis argues that DI is a millenarian movement that seeks to establish an Islamic state based on a literal interpretation of the Quran and the Sunnah, and that its violence is motivated by a sense of historical injustice and apocalyptic expectation. The thesis also analyzes the role of historicism in DI's discourse and practice, and how it shapes its identity, legitimacy, and resistance. The thesis contributes to the understanding of radical Islamism in Indonesia and beyond and offers a critical perspective on the concept of ?dark ethnography? as a methodological approach to studying violent and secretive groups. Reinterpreting the proclamation of the Islamic State of Indonesia on August 7, 1949, in Tasikmalaya, West Java, is a highly intriguing issue. The formation of Darul Islam (DI) or its formal name, the Islamic State of Indonesia (Negara Islam Indonesia, NII), has given birth to a great deal of speculations and misleading interpretations. Initially, it was assumed by a number of scientists that this event was a rebellion, separatist, and war against the newly formed unitary state of the Republic of Indonesia. Numerous oral and written sources (archives) assert that this "rebellion" was not an-attempt to undermine the republic, but rather a continuation of the 1945 proclamation and was "ordered" by General Soedirman to combat the Dutch military troops in West Java on behalf of Republic Indonesia. SM Kartosoewirjo also mobilized the Hizbullah and Sabilillah military forces in 1948, which would subsequently become the TII (Tentara Islam Indonesia, Indonesian Islamic Army). This NII resistance was also formed to oppose the forces of the Pasundan State and Westerling Troops. However, misunderstandings and claims arose that SM Kartosoewirjo was in revolt against the Soekarno's Republic, notably after the Stikker-Hatta Agreement, which historians have conducted little research on. Based on the results of archival research atthe Nationaal Archief in The Hague, the Netherlands, the Darul Islam incident (19491962) need to be reinterpreted due to its continued use of the red-and-white flag and the explanation of the proclamation that states the NII is a continuation of the 1945 proclamation. This will be very interesting to examine the concept of successor state, as NII is not a state that (will) arise to replace the previous nation, but rather as a newly transformed nation. The Islamic State of Indonesia is also a republic, as opposed to a monarchy or sultanate, which also differs from the image of a caliphate in modern times.