YardThe yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly 0.9144 meter. A distance of 1,760 yards is equal to 1 mile. The US survey yard is very slightly longer. The term, yard derives from the Old English gerd, gyrd etc., which was used for branches, staves and measuring rods.
Foot (unit)The foot ( () feet), standard symbol: ft, is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, , is a customarily used alternative symbol. In both customary and imperial units, one foot comprises 12 inches, and one yard comprises three feet. Historically, the "foot" was a part of many local systems of units, including the Greek, Roman, Chinese, French, and English systems. It varied in length from country to country, from city to city, and sometimes from trade to trade.
Treaty of TordesillasThe Treaty of Tordesillas, signed in Tordesillas, Spain, on 7 June 1494, and ratified in Setúbal, Portugal, divided the newly discovered lands outside Europe between the Portuguese Empire and the Spanish Empire (Crown of Castile), along a meridian 370 leagues west of the Cape Verde islands, off the west coast of Africa. That line of demarcation was about halfway between the Cape Verde islands (already Portuguese) and the islands visited by Christopher Columbus on his first voyage (claimed for Castile and León), named in the treaty as Cipangu and Antillia (Cuba and Hispaniola).
System of units of measurementA system of units of measurement, also known as a system of units or system of measurement, is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Instances in use include the International System of Units or () (the modern form of the metric system), the British imperial system, and the United States customary system.
Imperial unitsThe imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed through a series of Weights and Measures Acts and amendments. The imperial system developed from earlier English units as did the related but differing system of customary units of the United States. The imperial units replaced the Winchester Standards, which were in effect from 1588 to 1825.
Portuguese EmpireThe Portuguese Empire (Império Português), also known as the Portuguese Overseas (Ultramar Português) or the Portuguese Colonial Empire (Império Colonial Português), was composed of the overseas colonies, factories, and the later overseas territories governed by Portugal. It was one of the longest-lived colonial empires in European history, lasting almost six centuries from the conquest of Ceuta in North Africa, in 1415, to the transfer of sovereignty over Macau to China in 1999.