First visited by Vasco da Gama, Mozambique was colonized by the Portuguese in the early 16th century. It was a centre of the slave trade in the 17th and 18th centuries. Mozambique became an independent republic in 1975, after a ten-year armed struggle by the Frelimo liberation movement; civil war between the Frelimo government and the Renamo opposition followed until a peace agreement was signed in 1992. The country joined the Commonwealth in 1995.