Successor to the FRAP coalition, Popular Unity originally comprised most of the Chilean Left: the Socialist Party, the Communist Party, the Radical Party, the Social Democrat Party, the Independent Popular Action and MAPU ("Movimiento de Acción Popular Unitario"). They were later joined in 1971 by the Christian Left and in 1972 by the MAPU Obrero Campesino (a splinter group). UP also initially included the moderate Party of the Radical Left, but in 1972 it joined the opposition (inside the Confederation of Democracy).