The work was painted the year of her marriage to Prince Adolphus, Duke of Cambridge, the seventh son of George III.
Following the death of the prospective future heir to the throne Princess Charlotte in 1817, several of the King's sons got married in order to secure the succession for the reigning House of Hanover.
Her granddaughter Mary of Teck married her cousin George V and the current line of the royal family therefore descends from Augusta.
Beechey was an experienced portraitist by the time he depicted Augusta, having been a member of the Royal Academy since 1793.
Both works are now in the Royal Collection, Augusta's painting having been acquired from the Grand Duke Paul of Russia by Mary of Teck.