A league is an old unit of length that was common in Europe and Latin America, but is no longer an official unit in any nation)). It was derived from an ancient Celtic unit and adopted by the Romans as the leuga, and since the Middle Ages, many values have been specified in several countries). The length of a league varied depending on the country and the era, but it was generally defined as the distance a person could walk in about one hour). In English-speaking countries, the land league is generally accepted as three statute miles (4.83 km), although varying lengths from 7,500 feet to 15,000 feet (2.29 to 4.57 km) were sometimes employed. At sea, a league is three nautical miles (3.452 miles; 5.556 kilometres) )). The French league had different values at different times: 10,000, 12,000, 13,200, and 14,400 French feet, about 3.25 km to about 4.68 km). The league is also a subsidiary unit of length in the United States customary system, defined as 5,280 yards).