Following the defeat of South Vietnam by North Vietnamese forces, the first đồng was replaced by a new currency, known as the "liberation đồng", at a rate of 1 liberation đồng = 500 first đồng on September 22, 1975. The liberation đồng circulated until May 2, 1978, when the two Vietnamese currencies merged and the liberation đồng was replaced by the new Vietnamese đồng at a rate of 1 new đồng = 0.8 liberation đồng.