The United States assumed that this meant the immediate British evacuation of the Mosquito Coast, while the British argued that it only bound them to not expand further in Central America and that both the 1844 protectorate and the 1848 peace treaty were still valid. On November 21, the American steamer "Prometheus" was fired upon by a British warship for not paying port tariffs at Greytown. One of the passengers was Cornelius Vanderbilt, business magnate and one of the richest people in the United States. The British government apologized after the United States sent two armed sloops to the area.