Gustav III in the context of "Helsinki Court of Appeal"

The Russo-Swedish War of 1788–1790 was fought between Sweden and Russia from June 1788 to August 1790. The war was ended by the Treaty of Värälä on 14 August 1790 and took place concomitantly with both the Austro-Turkish War (1788–1791), Russo-Turkish War (1787–1792) and Theatre War. The war was, overall, mostly insignificant for the parties involved.

King Gustav III of Sweden initiated the war for domestic political reasons, hoping to gain support from the opposition. Despite forming an alliance with the Ottoman Empire, Sweden failed to secure support from Great Britain, the Dutch Republic, and Prussia. Sweden's initial plan to attack Saint Petersburg and instigate a coup to depose Empress Catherine II did not materialize. The war led to Denmark–Norway declaring war on Sweden, but peace was eventually signed on 9 July 1789 after diplomatic intervention by Great Britain and Prussia.

Charles XIII or Carl XIII (Swedish: Karl XIII; 7 October 1748 – 5 February 1818) was King of Sweden from 1809 and King of Norway from 1814 to his death. He was the second son (and younger brother to King Gustav III) of King Adolf Frederick of Sweden and Louisa Ulrika of Prussia, sister of Frederick the Great.

Though known as King Charles XIII in Sweden, he was actually the seventh Swedish king by that name, as Charles IX (reigned 1604–1611) had adopted his numeral after studying a fictitious history of Sweden. In Norway, he is known as Charles II.

The history of Sweden from 1772 to 1809 is better known as the Gustavian era of kings Gustav III and Gustav IV Adolf, as well as the reign of King Charles XIII.

The Treaty of Värälä (sometimes known as the Treaty of Wereloe) was signed in Värälä, Elimäki Municipality, Finland, between Russia (represented by Otto Heinrich Igelström) and Sweden (represented by Gustaf Mauritz Armfelt). It was signed on 14 August 1790 and concluded the Russo-Swedish War. The treaty confirmed status quo ante bellum with respect to the borders; however, Russia's right to interfere with Swedish interior affairs from the Treaty of Nystad was expressly revoked. The provisions of the previous Treaty of Åbo were basically confirmed.

A year later, on 19 October 1791, a convention was signed in Stockholm, whereby the countries pledged to assist each other in case of foreign attack. The treaty anticipated the First Coalition in its being directed against Revolutionary France. Catherine bound herself to pay her new ally annual subsidies amounting to 300,000 rubles. Gustav III had sent to his cousin, Catherine II of Russia, a letter in which he besought her to "forget the war as a passing cloud" and invoked their common blood as his claim to enjoy amitie with his cousin.

Louisa Ulrika of Prussia (Swedish: Lovisa Ulrika; German: Luise Ulrike; 24 July 1720 - 16 July 1782) was Queen of Sweden from 1751 to 1771. She was married to king Adolf Frederick and she was queen mother during the reign of king Gustav III.

Coronations of the Swedish monarchs took place in various cities during the 13th and 14th centuries, but from the middle of the 15th century onward in the cathedrals of Uppsala or Stockholm, with the exception of the coronation of Gustav IV Adolf, which took place in Norrköping in 1800. Earlier coronations were also held at Uppsala, the ecclesiastical center of Sweden. Prior to Sweden's change to a hereditary monarchy, the focus of the coronation rite was on legitimising an elected king.