 According to Pew research center, two-thirds of the Muslim population of Tanzania is Sunni, while the rest is either Shia (20%) or Ahmadi (15%) besides a smaller subset of Ibadism and nondenominational Muslim practitioners.The earliest concrete evidence of a Muslim presence in the African Great Lakes is the foundation of a mosque in Shanga on Pate Island, where gold, silver and copper coins dated from 830 were found during an excavation in the 1980s.Islam arrived to Tanzania with the Arab slave traders.