Patuan Besar Ompu Pulo Batu, better known as Si Singamangaraja XII (1849 – 17 June 1907), was the last priest-king of the Batak peoples of north Sumatra.
In the course of fighting a lengthy guerrilla war against the Dutch colonisation of Sumatra from 1878 onwards, he was killed in a skirmish with Dutch troops in 1907.
He was declared a National Hero of Indonesia in 1961 for his resistance to Dutch colonialism.