The half sovereign was first introduced in 1544 under Henry VIII.
After 1604, the issue of half sovereigns, along with gold sovereigns, was discontinued until 1817, following a major revision of British coinage. Production continued until 1926 and, apart from special issues for coronation years, was not restarted until 1980.
It was also used extensively in Australia, until 1933.
Modern half sovereigns, from 1817 onwards, have a diameter of 19.30 mm, a thickness of ~0.99 mm, a weight of 3.99 g, are made of 22 carat (916⅔ %) crown gold alloy, and contain 0.1176 troy ounces (3.6575 g) of gold.
The reverse side, featuring St George slaying a dragon, was designed by Benedetto Pistrucci.