the first union in zanzibar, where the tanganyikan labor unions were not active, was the seamen's union, which was founded in 1955. there had been a strike by the island's dock workers in 1948, but no organized labor movement until 1955. a wave of union foundings followed that of the seamen's union, but these organizations did not have many members as zanzibar was only scarcely populated and the socio-economic activities were few. in 1956, the federation of zanzibar and pemba trade unions (zpfl) was founded with assistance from tanganyikan unionists. during the first half of the 1960s the zanzibari labor movement flourished. during the 1964 revolution, the labor movement collaborated with peasants to overthrow the sultan.