Wikipedia
The term Parmalim describes the followers of the Malim religion, the modern form of the traditional Batak religion. People not familiar with the Batak language may erroneously assume Parmalim is the name of the religion rather than its practitioners.
At the end of the 19th and in the beginning of the 20th century the Parmalim movement, which originated in Toba lands spread to other areas of the Batak lands. Especially in the lower Karo lands, the 'dusun'm the Malim religion, became very influential as an expression of anti-colonial sentiments at the turn of the 20th century. Today the majority of Parmalim are Toba Batak. The largest of the several existing Parmalim groups has its centre in Huta Tinggi in the vicinity of Laguboti on the south shore of Lake Toba.
The Malim religion has some similarities with Islam, including a prohibition on the consumption of pork and of blood, and the practice of wearing turbans. Modern Malim deny that these practices were derived from Islam.
One of the first leaders of the Parmalim movement was Guru Somalaing Pardede. Modern Parmalim trace their heritage to Sisingamangaraja XII, a Batak leader in the fight against the Dutch, whose spirit is still alive in his successors. According to Raja Marnakkok Naipospos, a modern Parmalim leader, the faith has often be slandered as devil worship 'Campaigns branding Parmalim as devil worshippers still exist today', he said, 'Batak not familiar with Malim regard it as a heresy. But in fact, Malim recognizes the existence of the one and only Almighty God'. (Mula Jadi Na Bolon in Batak mythology).
Masashi Hirosue has written an article on the history of the Parmalim movement entitled "The Batak Millenarian Response to the Colonial Order" published in the Journal of Southeast Asian Studies, Vol. 25, Singapore, 1994. In his book "Toba na Sae; Sejarah lembaga sosial politik abad XIII-XX ( Jakarta: Komunitas Bambu, 2004) the Indonesian poet Sitor Situmorang describes the encounter between Guru Somalaing and Elio Modigliani who later wrote a book about his journeys into the independent Batak lands in his book "Fra i Batacchi indipendenti; Viaggio di Elio Modigliani" (1892 Roma: Società Geografica Italiana).