In this usage, obverse means the front face of the object and reverse means the back face. The obverse of a coin is commonly called heads, because it depicts the head of a prominent person. In fields of scholarship outside numismatics, the front is more commonly used than obverse. For prints and drawings with material on both sides the one judged as more significant will be the recto, a convention now exists typically to display the obverse to the left and the reverse to the right in photographs and museum displays, but this is not invariably observed. Following this principle, in the most famous of ancient Greek coins, the tetradrachm of Athens, the obverse is the head of Athena, similar versions of these two images, both symbols of the state, were used on the Athenian coins for more than two centuries. The opposite side may have varied from time to time and this change happened in the coinage of Alexander the Great, which continued to be minted long after his death. The various Hellenistic rulers who were his successors followed his tradition and this script alone style then was used on nearly all Islamic coinage until the modern period. The type of Justinian II was revived after the end of Iconoclasm, without images, therefore, it is not always easy to tell which side will be regarded as the obverse without some knowledge. After 695, Islamic coins avoided all images of persons and usually, the side expressing the Six Kalimas is usually defined as the obverse. The form of currency follows its function, which is to serve as an accepted medium of exchange of value. Traditionally, most states have been monarchies where the person of the monarch, if not provided for on the obverse, the reverse side usually contains information relating to a coins role as medium of exchange. Additional space typically reflects the countrys culture or government, or evokes some aspect of the states territory. Regarding the euro, some regarding the obverse and reverse of the euro coins exists. This rule does not apply to the coins as they dont have a common side. A number of the used for obverse national sides of euro coins were taken from the reverse of the old pre-euro coins of some individual countries. Several countries continue to use portraits of the monarch and the Republic of Ireland continues to use the State Arms. The Chrysanthemum Crest was no longer used after the war, and so, the side on which the date continues to be regarded as the reverse. Following ancient tradition, the obverse of coins of the United Kingdom almost always feature the head of the monarch
Image: Antoninianus Tranquillina Gordian III s 2539
A Roman imperial coin of Marcus Claudius Tacitus, who ruled briefly from 275 to 276, follows the convention of obverse and reverse coin traditions.
Solidus of Justinian II after 705. Christ is on the obverse (left), the emperor on the reverse.