The current flag of Bahrain was adopted in 2002. The flag is coloured red and is separated by a white band with five triangles. The colour of red is the traditional colour for the flags of the states in the Persian Gulf. The oldest known flags of Bahrain were plain red, but in 1820 the white was added to as a result of a treaty with Great Britain to indicate a truce. The serrated edge was added in 1932 to distinguish the flag from the surrounding nations in the Persian Gulf and in 2002 the number of triangles was reduced to five. The five triangles on the flag were set to represent the five pillars of Islam.