Northeast Europe (1780–1791 CE): Enlightened Reform, Military Ambitions, and Scientific Innovation

Between 1780 and 1791 CE, Northeast Europe experienced a dynamic period characterized by enlightened reforms, ambitious military campaigns, significant scientific discoveries, and sustained economic and cultural development. Sweden under Gustav III pursued renewed military objectives alongside internal reforms, Denmark–Norway maintained strategic neutrality and domestic modernization, and Prussia under Frederick the Great and subsequently Frederick William II continued administrative efficiency and economic stability. The era was also marked by notable scientific advancements, exemplified by the groundbreaking work of Swedish chemist Peter Jacob Hjelm.

Sweden: Gustav III’s Enlightened Absolutism and Military Ambitions

King Gustav III (r. 1771–1792), having restored royal absolutism in Sweden in 1772, continued extensive internal reforms aimed at strengthening the monarchy, modernizing administration, and advancing cultural life. Alongside domestic reforms, Gustav pursued ambitious foreign policy objectives, notably attempting to revise the territorial outcomes of the earlier Great Northern War. In 1788, Sweden declared war against Russia, seeking to reclaim lost territories along Finland’s eastern border.

The Russo-Swedish War and the Anjala League Mutiny

During the ensuing conflict (1788–1790), known as the Russo-Swedish War, an important internal incident was the mutiny of a faction of Finnish officers within the Swedish military, known as the Anjala League. The mutineers, led prominently by former Swedish army colonel Göran Sprengtporten, aimed to avoid provoking severe Russian retaliation against Finland. Although swiftly suppressed and lacking broad support among Finnish officers, the mutiny highlighted increasing war-weariness among many Finns, particularly Finnish nobles, who were growing weary of Finland's frequent role as a battleground between Sweden and Russia.

Due to Russia’s simultaneous military commitments in a major conflict against the Ottoman Empire, Sweden secured an advantageous diplomatic settlement in the Treaty of Värälä (1790), effectively ending the conflict without territorial changes. Thus, despite Gustav III’s ambitious objectives, the territorial boundaries of Finland remained unchanged, preserving the status quo while leaving underlying tensions unresolved.

Scientific Advancement: Hjelm’s Isolation of Molybdenum

During this period, Sweden also witnessed significant scientific progress. In 1781–1782, Swedish chemist Peter Jacob Hjelm, encouraged by colleague Carl Wilhelm Scheele, successfully isolated the metal molybdenum. By heating a paste composed of molybdenum oxide and linseed oil at high temperatures in a crucible, Hjelm achieved the first-ever isolation of this element. Naming the newly discovered metal from the Greek molybdos, meaning “lead,” Hjelm’s achievement represented a major advancement in European chemical science, underscoring Sweden’s continued prominence in scientific and industrial chemistry research.

Danish–Norwegian Neutrality and Enlightened Domestic Reforms

Under the rule of King Christian VII (r. 1766–1808), Denmark–Norway continued to focus on domestic modernization and cautious neutrality in regional politics. Economic prosperity increased through investments in infrastructure, agriculture, and maritime commerce. Copenhagen became increasingly vibrant as a center of commerce, culture, and Enlightenment-inspired education, maintaining stability and economic growth amidst broader European geopolitical uncertainties.

Prussian Stability under Frederick II and Frederick William II

Prussia under Frederick II (Frederick the Great) (r. 1740–1786), and later under Frederick William II (r. 1786–1797), maintained disciplined governance, economic stability, and strategic territorial control. Frederick II’s enlightened reforms in education, administration, and agriculture persisted, bolstering Prussia’s economic and administrative efficiency, especially in territories around Königsberg (Kaliningrad).

Economic Prosperity and Urban Stability

Key urban centers across Northeast Europe, including Stockholm, Copenhagen, Königsberg, Riga, and Reval (Tallinn), continued to thrive economically, benefiting from maritime trade, improved infrastructure, and stable governance. Regional economic integration deepened, supported by expanding merchant networks and commercial growth, contributing substantially to urban prosperity and stability.

Finland: Agricultural Improvements and the Burden of Warfare

Finland, still under Swedish rule, experienced continued agricultural productivity and internal economic stability. Improvements in scientific agriculture—such as the continued use of potatoes, building upon earlier advancements—enhanced food security and economic resilience. However, the Russo-Swedish War of 1788–1790 reinforced concerns among Finns about the persistent vulnerability and risks associated with Finland’s geopolitical position, as highlighted by the Anjala League incident.

Stability and Incremental Progress in the Baltic Territories

The Baltic territories—Estonia, Latvia, and Lithuania—experienced steady economic growth and internal stability. Predominantly governed by Baltic-German nobility, these regions maintained relative tranquility, with urban centers such as Riga and Reval thriving economically and culturally. Enlightenment-inspired local reforms and educational advancements gradually enhanced regional prosperity and stability.

Cultural Flourishing and Intellectual Life

Cultural and educational institutions flourished across Northeast Europe. King Gustav III significantly patronized arts and sciences in Sweden, establishing influential institutions including the Swedish Academy (Svenska Akademien) in 1786. Denmark–Norway and Prussia continued to nurture academic and cultural development, supporting Enlightenment ideals and intellectual advancement throughout the region.

Diplomatic Pragmatism and Regional Realignment

Diplomatic interactions during this era remained pragmatic and cautious. Sweden’s brief military ambition against Russia revealed clear limitations on Swedish geopolitical influence and highlighted Finland’s vulnerability. Denmark–Norway maintained neutrality and stability, while Prussia skillfully avoided involvement in destabilizing conflicts, preserving regional stability and internal growth.

Legacy of the Era

The period from 1780 to 1791 CE significantly impacted Northeast Europe through Sweden’s ambitious yet ultimately inconclusive war efforts, critical internal political events like the Anjala League mutiny, and landmark scientific advancements exemplified by Hjelm’s discovery of molybdenum. These developments shaped regional geopolitical relationships, reinforced internal political and economic stability, and promoted continued scientific and cultural vitality, laying a strong foundation for future historical trajectories.

King Gustav III of Sweden, who in 1772 had reimposed absolutism in Sweden, also tries to alter the verdict of the Great Northern War.

In 1788 Sweden declares war against Russia with the intention of regaining territory along Finland's eastern frontier.

A significant incident during this war is the mutiny of a group of Finnish military officers, the Anjala League, the members of which hope to avert Russian revenge against Finland.

A leading figure in the mutiny is a former colonel in the Swedish army, Goran Sprengtporten.

Most Finnish officers do not support the mutiny, which is promptly put down, but an increasing number of Finns, especially Finnish nobles, are weary of Finland's serving as a battleground between Sweden and Russia.

Because of Russia's simultaneous involvement in a war with the Ottoman Empire, Sweden is able to secure a settlement in 1790 in the Treaty of Varala, which ends the war without altering Finland's boundaries.

King Gustav III of Sweden initiates a conflict with Russia for domestic political reasons, as he believes that a short war will leave the opposition with no recourse but to support him.

Despite establishing himself as an autocrat in a bloodless coup d'état that ended parliamentary rule in 1772, his political powers do not give him the right to start a war.

Also he is becoming increasingly unpopular, an issue which had become obvious during the parliament session of 1786.

This unpopularity is also encouraged by Russia, which believes an autocratic king to be a threat to its interests.

However, Russian support for his opposition does not go unnoticed by Gustav III, and is one of the reasons why he thinks of the war as inevitable.

The Western powers—specifically Great Britain, the Dutch Republic and the Kingdom of Prussia—are alarmed by a string of Russian victories in the Russo-Turkish War (1787–92) and lobby for the war in the north, which would divert the attention of Catherine II of Russia from the southern theater.

It is at their instigation that Gustav concludes an alliance with the Ottoman Empire in the summer of 1788.

However, only the Ottoman Empire is willing to ally with Sweden while Great Britain, the Dutch Republic, and Prussia reject efforts to form an alliance.

Gustav's main aim is to recapture some of the territory in Finland that had been lost to the Russians in the war of 1741–43.

One Swedish army is to advance through Finland; a second army, accompanied by the Swedish coastal flotilla, is to advance along the Finnish coast into the Gulf of Finland; while a third army sails with the Swedish battle fleet in order to land at Oranienbaum to advance on Saint Petersburg,  intending to catch the Russian fleet by surprise.

The plan is to attack Kronstadt and land a force to assault the Russian capital.

The goal is to instigate a coup de état in Russia and depose Empress Catherine II.

Sveaborg is set as the forward base of operations for the campaign.

However, the whole concept is based on the assumption that the Swedish open sea fleet will be able to decisively defeat its Russian counterpart.

Incidentally, Russian forces are not totally unprepared for the war, since the bulk of the Russian Baltic Fleet is planned to be transferred against the Ottoman Empire and has made preparations of its own for war.
 
War is far from popular, even less so in the eastern part of Sweden (modern day Finland).

Even senior military leaders voice their opposition to the plans to go to war.

Especially among  the officers of the army, unrest spreads widely.

This can partly be explained by the still-remaining supporters of Georg Magnus Sprengtporten's plans for Finnish independence.

The Swedish open-sea fleet had sailed from Karlskrona on June 9, 1788, with Duke Charles of Södermanland as its commander.

On June 21, the fleet meets a Russian squadron off Saaremaa island and after chasing the Russians down tries to provoke a conflict by demanding Russians render honors to the Swedes from which Russians had been exempted in the previous peace treaties.

Vice Admiral Wilhelm von Dessin, who commands the small Russian squadron, agrees to render honors to the Duke Charles but not to the Swedish flag and manages to defuse the threatening situation and continue towards Copenhagen

Since the Swedish want to avoid initiating the conflict they have lost their chance to provoke the Russians into war and are left empty-handed.

A head tailor of the Royal Swedish Opera had received an order in 1788 to sew a number of Russian military uniforms that later are used in an exchange of gunfire at Puumala, a Swedish outpost on the Russo-Swedish border, on June 27, 1788.

The staged attack, which causes outrage in Stockholm, is to convince the Riksdag of the Estates and to provide Gustav with an excuse to declare a "defensive" war on Russia.

This is important since Gustav III does not have the constitutional right to start an offensive war without the agreement of the estates, who have already made clear that their acquiescence will not be forthcoming.

The coastal fleet's Stockholm squadron had departed for Finland on June 25, carrying over nine thousand troops.

It reaches its destination of Sveaborg on July 2 and starts constructing an encampment on the island of Sandhamn (Santahamina), next to Helsingfors.

The Swedish fleet had been notified on July 7 that a state of war with Russia was in effect, and already on July 8 had surprised two unprepared Russian frigates—thirty-two gun Jaroslavets (Jarislawits) and twenty-four gun Hektor (Gektor)—which are promptly captured together with their crew of four hundred and fifty men.

The Swedish fleet meets a Russian fleet sailing under the command of Admiral Samuel Greig and fight an engagement near Hogland Island, in the Gulf of Finland, in which neither side manages to gain advantage.

Unusually for a naval battle, both sides capture one ship.

The Swedes fare slightly better in the artillery duel leaving four Russian ships dead in the water but fail to capitalize their success, while all Swedish ships are able to set sail after the battle.

The Russians suffer the worst casualties, losing three hundred and nineteen to five hundred and eighty men killed compared with between two hundred and three hundred Swedes, but the battle is a strategic victory for the Russians because Greig had done enough to prevent the Swedish landing.

One reason why the fight ends, even though Swedish battle fleet has the advantage, is that the Swedish fleet is rapidly running out of ammunition, especially for its heavier cannons, and has to depart.

The Swedes, upon returning to Sveaborg to repair and resupply Duke Charles' fleet, find that the island fortress had been stocked only with the coastal fleet in mind, which among other things means that it has not stored ammunition for the heavy cannons of the open sea fleet and lacks suitable stocks of equipment required to repair large sailing ships.

The coastal fleet's Sveaborg squadron under Colonel Mikael Anckarsvärd had been readied for action by mid-June and had departed on July 26 for Frederikshamn, carrying six thousand men, while a four thousand-strong unit advanced on land under General Carl Gustaf Armfeldt. 

The Swedish coastal fleet clashes briefly with a group of Russian galleys outside Frederikshamn (Hamina) on July 28, and forces them to retire within the protection of the fortifications.