Mirza Ghulam Ahmad established the Community (or Jamāʿat) on 23 March 1889 by formally accepting allegiance from his supporters. Since his death, the Community has been led by a number of Caliphs and has spread to 210 countries and territories of the world as of 2017 with concentrations in South Asia, West Africa, East Africa, and Indonesia. The Ahmadis have a strong missionary tradition and formed the first Muslim missionary organization to arrive in Britain and other Western countries.[28][29][30][31][32] Currently, the Community is led by its Caliph, Mirza Masroor Ahmad, and is estimated to number between 10 and 20 million worldwide.[33][34][35][36]