Large laureate bust ('Bull Head') right, legend ('George the Third by the Grace of God') around, date below.

George III (George William Frederick; 1738–1820) was King of Great Britain and Ireland from 25 October 1760 until the union of the two countries on 1 January 1801, after which he was King of the United Kingdom of Great Britain and Ireland until his death.

His life and reign, which were longer than any other British monarch before him, were marked by a series of military conflicts involving his kingdoms, much of the rest of Europe, and places farther afield in Africa, the Americas and Asia. Early in his reign, Great Britain defeated France in the Seven Years' War, becoming the dominant European power in North America and India. However, many of Britain's American colonies were soon lost in the American Revolutionary War. Further wars against revolutionary and Napoleonic France from 1793 concluded in the defeat of Napoleon at the Battle of Waterloo in 1815.

In the later part of his life, George III had recurrent, and eventually permanent, mental illness. Although it has since been suggested that he had the blood disease porphyria, the cause of his illness remains unknown. After a final relapse in 1810, a regency was established, and George III's eldest son, George, Prince of Wales, ruled as Prince Regent.

Depicts crowned escutcheon of the United Kingdom surrounded by the Order of the Garter with "Great George" below (the knight on horseback). The motto HONI SOIT QUI MAL Y PENSE appears on a circular belt. The lower left garniture of the shield has the incuse initials WWP (for William Wesley Pole, master of the mint) and at lower right incuse W (for Thomas Wyon, chief engraver).

The royal coat of arms of the United Kingdom, or the Royal Arms for short, is the official coat of arms of the British monarch. The shield is quartered, depicting in the first and fourth quarters the three passant guardant lions of England; in the second, the rampant lion and double tressure flory-counterflory of Scotland; and in the third, a harp (a winged female) for Ireland.

The Order of the Garter (formally the Most Noble Order of the Garter) is an order of chivalry founded by Edward III in 1348 and regarded as the most prestigious British order of chivalry in England and the United Kingdom. The star, which is worn pinned to the left breast, was introduced in the 17th century by King Charles I and is a colourfully enamelled depiction of the heraldic shield of St. George's Cross, encircled by the Garter, which is itself encircled by an eight-point silver badge. Each point is depicted as a cluster of rays, with the four points of the cardinal directions longer than the intermediate ones.

The Great George, which is worn suspended from the collar, is a colourfully enamelled (sometimes jewelled) three-dimensional figure of St. George the Martyr on horseback slaying a dragon.

Honi soit qui mal y pense is a French maxim used as the motto of the British chivalric Order of the Garter. It is translated as "May he be shamed who thinks badly of it".

BRITANNIARUM REX FID: DEF: means King of the Britons Defender of the Faith.