 Smaller numbers were settled in Liberia, a colony established by the United States.Shortly after the British Parliament outlawed British participation in the slave trade in 1807, the Royal Navy started to patrol the African coast and high seas, seizing British vessels suspected of engaging in the slave trade.After the Congress of Vienna and the ratification of various international agreements to restrict or outlaw the transatlantic trade, the West Africa Squadron, and to a lesser extent maritime patrols flying under the flags of Spain, Portugal, the Netherlands, Brazil, and the United States, also intercepted ships suspected of trafficking slaves in contravention of treaty provisions.