A combination of reformist thoughts and the growing sense of sovereignty had led to the brief development of Islam as a vehicle for the political struggle against the Dutch colonialism. The earliest example is Padri movement from Minangkabau. Padri movement was inspired by Wahhabism during its inception, and aimed at purification of Islam in Indonesia reciprocally. The movement eventually turned into a struggle against Dutch colonialism during the Padri War (1803–1837). One of the leaders, Tuanku Imam Bonjol, is declared a National Hero of Indonesia. In the early 20th century, Sarekat Islam was developed as the first mass nationalist organization against colonialism. Sarekat Islam championed Islam as a common identity among vast and diverse ethnic and cultural compositions throughout the archipelago, especially against the perceived enemy of the Christian masters. The educational institutions such as Jamiat Kheir also supported the development. In the process, Islam gave the sense of identity which contributed to the cultivation of Indonesian nationalism. Under this circumstance, early Indonesian nationalists were eager to reflect themselves as a part of the "ummah" (worldwide Islamic community). They also had interests in Islamic issues such as re-establishment of Caliphate and the movements such as pan-Islamism. For these reasons, Dutch colonial administration saw Islam as a potential threat and treated the returning pilgrims and students from the Middle East with particular suspicion. Similar Islamic-nationalist organization Union of Indonesian Muslims (PERMI) faced severe crackdown by the Dutch colonial government, leading to the arrest of its members including Rasuna Said.