An unpredictable meteor, Gustavus, born into the house of Holstein-Gottorp, became King of Sweden in 1771 on the death of his lacklustre father, Adolf Fredrik. In 1756, Adolf Fredrik had been humiliated through a failed coup that attempted to recover some power for the crown, which had lost it in the Swedish ‘Age of Liberty’ after the death of Charles XII in conflict in 1718. In contrast, helped by widespread dissatisfaction, the 26-year-old Gustav staged a bloodless coup on 19 August 1772. The powers of the Crown were restored, the Senate was arrested, and the Riksdag (Parliament) was reconvened.

A new constitution, with greater powers for the crown, was approved on 21 August, by which Gustav regained the power to summon and dismiss the Riksdag, to appoint ministers and to propose legislation. The preamble of the new constitution declared that the king had tried ‘to promote the advancement, strength and welfare of this realm, as well as the improvement, safety and happiness of our loyal subjects… the present situation of the country requires an unavoidable amendment of the Fundamental Laws, adapted to the above-mentioned salutary purpose’.

The ‘Age of Liberty’ was dismissed: ‘Under the name of the blessed Liberty, several of our fellow subjects have formed an Aristocracy, so much more intolerable, as it had been framed under licentiousness, fortified by self-interest and severities, and finally supported by foreign powers, to the detriment of the whole society.’

Gustav claimed to be re-establishing the former constitution. Touring Sweden in 1768, he had written to his brother from the small settlement of Avesta: ‘At Stockholm, where one lives in plenty, it is impossible to imagine the condition of these poor people.’ In 1771, he observed that the Riksdag was ‘no pleasant spectacle for any but cosmopolitan philosophers’. The political system of the ‘Age of Liberty’ was indeed regarded as corrupt and prone to sectional interests. Power politics were involved. France backed the coup.

One of the most talented of the enlightened despots, Gustav instigated reforms that included limited religious tolerance, a reduction in the number of capital offences, and the reform of the currency. He sought and welcomed the praise of the French philosopher, Voltaire. In Rome in 1783, Gustav called upon Pius VI and attended a Christmas Mass at St Peter’s to publicise his tolerance of Catholics in Sweden. In 1786, he both re-organised the Academy of Letters and founded a Swedish Academy devoted to Swedish language and literature, selecting the first members, including the leading poets of the period.

Gustav was a Freemason. Indeed, in 1788, Hugh Elliott, the British envoy in Copenhagen, referred to him as an adept of ‘mysterious arts’ and wrote that he was ‘infatuated’ by ‘freemasonry combined with prophecy’, a reference to the Illuminati. However, Gustav paid insufficient attention to the need to win elite support, and preferred to work with favourites rather than through his council. After he failed to win widespread support at his first Riksdag under the new constitution, that of 1778-9, where his proposed religious and penal reforms were criticised, it is not surprising that he displayed little interest in his constitutional limitations.

In his later years, Gustav became increasingly interested in a bolder foreign policy. He sought to break the link between his opponents: Denmark, which ruled Norway, and Russia. Prevented from invading Norway in 1784 by Russian pressure, he attacked Russia in 1788, threatening St Petersburg. Gustav ignored the constitutional prohibition on offensive war without the consent of the Riksdag. The war was begun when Swedish soldiers disguised as Russians staged a border incident at Puumala. However, Gustav’s army was not in good shape, and a naval battle in the Gulf of Finland on 17 July 1788, in which the Swedes were hindered by ammunition shortages, denied Gustav the control which he needed both for his military operations in Finland and if he was to carry out an amphibious attack on St Petersburg. An overland offensive was mounted without success. Unsurprisingly, the British diplomat Sir Robert Murray Keith described Gustav as the ‘hare-brained heir and imitator of Charles XII’.

The war, which ended in 1790, precipitated domestic tension in Sweden, especially among the Finns. The opposition of the aristocratic officer corps handicapped Gustav, as did the Anjala Confederation, a league of Finnish officers who declared to Catherine the Great that they sought perpetual peace with Russia and would not fight except in defence of their homeland. To break his opponents, Gustav staged a new constitutional coup in 1789. In co-operation with the non-noble Estates, he pushed through an Act of Union and Security, under which the crown’s power to introduce laws was considerably extended. Most public offices were opened to commoners, and peasants’ rights to purchase land were extended.

Russia’s attempt to thwart this policy by supporting the anti-royalist noble opposition failed. The clear relationship of domestic and international strength was displayed by Gustav’s reasonable success in the rest of the war. Under pressure from Gustav’s subsidy treaty with the Turks (1789) and his search for co-operation with Poland, Catherine concluded peace in 1790. Sweden made no territorial gains but won a recognition of the constitution of 1772 and a promise not to interfere in Swedish politics. This promise was fulfilled in the instructions to the new Russian mission to Stockholm.

From 1790, the situation became increasingly volatile. Gustav, who had observed ‘I am myself a democrat’, planned another coup to establish a new constitution with a re-organised legislature. He was greatly affected by the French Revolution and made plans to act against France. The British envoy reported him saying in March 1792 that ‘popular assemblies were dangerous only when Princes did not know how to manage them; and on my remarking that the manner of transacting the business of the Swedish Diet, in a committee in which His Majesty could overawe and direct debates, was a particular advantage to him, he replied that this would be a great disadvantage to Louis XVI’.

An aristocratic conspiracy led to the mortal wounding of Gustav by Johan Jakob Anckarström that month. At midnight on 16 March 1792, at the masked ball in the Stockholm opera house, Gustav, identifiable by his breast star of the Royal Order of the Seraphim, was mortally wounded by gunshot in the lower back. He was able to thwart the uprising but died on 29 March from septicaemia. Anckarström fled the opera, but his discarded pistol was found and he was subsequently tried and executed.

There is no basis for Anckarström’s operatic presentation by both Auber and Verdi as a victim of Gustav’s love for his wife, nor for Gustav’s supposed pardon of the conspirators. Anckarström defended himself at his trial by accusing Gustav of having violated his contract with the nation, and his young noble supporters saw Gustav as a despot while they espoused social equality and popular sovereignty, and praised the French Revolution. The bulk of the noble opposition, however, did not share these views and were shocked by the assassination.

In 1792, a British caricature, possibly by William Dent, called ‘Royal Masquerade’, or ‘the European Plotters Discovered and Defeated and the Ex-Princes Crossed in their Masked Design against Liberty’, showed Gustav III, his belt marked Tyranny, being attacked and killed by a smiling skeleton, while Liberty presided in the character of Death. His son and successor, Gustav IV (r. 1792-1809), had a less lurid overthrow. Displaying signs of instability. and with Sweden challenged by the Russian conquest of Finland, he was deposed in a conspiracy by aristocratic army offiers and replaced by his uncle Charles XIII. Transported to Germany, he finally died, poor and lonely, in Swiss exile in 1837.