Bronze sestertius of Nero (54-68 CE)

Artist: Unknown Roman Artist Primary

Imperial
Refers to the period in history and the style of art that developed when the Roman Republic ceased to exist and Rome expanded its territory and was ruled by emperors. The period is generally considered to begin with Octavian's victory at the Battle of Actium in 31 BCE, and to last through the rule of the Severans. For later emperors, see "Late Antique." For the period and culture of the Holy Roman Empire, use "Holy Roman Imperial." Note that some classifications include the Tetrarchic, Constantinian, and the Holy Roman Empire in the "Roman Empire."

bronze
Refers to a broad range of alloys of copper, specifically any non-ferrous alloy of copper, tin, and zinc or other trace metals. Bronze was made before 3,000 BCE -- possibly as early as 10,000 BCE, although its common use in tools and decorative items is dated only in later artifacts. The proportions of copper and tin vary widely, from 70 to 95 percent copper in surviving ancient artifacts. Because of the copper base, bronze may be very malleable and easy to work. By the Middle Ages in Europe, it was recognized that using the metals in certain proportions could yield specific properties. Some modern bronzes contain no tin at all, substituting other metals such as aluminum, manganese, and even zinc. Historically, the term was used interchangeably with "latten." U.S. standard bronze is composed of 90% copper, 7% tin and 3% zinc. Ancient bronze alloys sometimes contained up to 14% tin.

numismatics
Study of coins, tokens, medals, paper money, and objects closely resembling them in form or purpose.

coins
Pieces of metal stamped by government authority for use as money.

public domain
Land owned and controlled by the state or federal government. Also, the status of publications, products, and processes that are not protected under patent or copyright.