Portuguese Congo (Cabinda) was established a Portuguese protectorate by the 1885 Treaty of Simulambuco. Sometime during the 1920s, it became incorporated into the larger colony (later the overseas province) of Portuguese Angola. The two colonies had initially been contiguous, but later became geographically separated by a narrow corridor of land, which Portugal ceded to Belgium allowing Belgian Congo access to the Atlantic Ocean. Following the decolonisation of Portuguese Angola with the 1975 Alvor Agreement, the short-lived Republic of Cabinda unilaterally declared its independence. However, Cabinda was soon overpowered and re-annexed by the newly proclaimed People's Republic of Angola and never achieved international recognition.