Events on February 11 in history

The assault on Copenhagen by Swedish forces is beaten back with heavy losses.

The **Battle of Copenhagen**, also prominently referred to as the **Assault on Copenhagen**, unfolded on 11 February 1659. This pivotal engagement represented a critical moment during the broader **Second Northern War** (1655–1660), occurring as the Swedish army maintained its relentless **siege of Copenhagen**, the capital of Denmark.

The Second Northern War and the Strategic Siege of Copenhagen

The **Second Northern War**, known historically by various names including the Karl Gustav War, was a brutal and expansive conflict that engulfed much of Northern and Central Europe. Primarily, it pitted the burgeoning Swedish Empire, under the ambitious and aggressive leadership of King Charles X Gustav, against a coalition of powers including Denmark-Norway, the Polish-Lithuanian Commonwealth, Russia, Brandenburg-Prussia, and the Habsburg Monarchy. For Sweden, the war aimed to consolidate its dominance in the Baltic region, a strategic objective often referred to as the Dominium Maris Baltici (control of the Baltic Sea).

In 1658, following audacious marches across the frozen Danish Belts, King Charles X Gustav had forced Denmark into the Treaty of Roskilde, a humiliating peace that ceded significant territories. However, his ultimate ambition was to completely dismantle the Danish kingdom and annex its remaining territories, transforming the Baltic into a Swedish inland sea. This led to a renewed attack and the subsequent **siege of Copenhagen**, which commenced in August 1658. Copenhagen, as Denmark's capital and a vital strategic port controlling the Øresund (the Sound), was paramount. Its capture would effectively end Danish sovereignty.

For months, the Swedish forces had encircled the city, hoping to starve its defenders and civilian population into submission. However, the resilient Danish King Frederick III, bolstered by a determined citizenry and the strategic support of Dutch naval forces, refused to yield. The prolonged siege drained Swedish resources and morale, prompting King Charles X Gustav to seek a decisive, albeit risky, military solution: a direct assault on the heavily fortified city.

A Desperate Gamble: The Swedish Assault Plan

Facing a drawn-out and costly siege, King Charles X Gustav made the audacious decision to launch a full-scale assault on Copenhagen. The unusually severe winter of 1658-1659 proved to be both an opportunity and a challenge. The Danish straits and the surrounding waters of the Øresund had frozen solid, transforming the city's natural water defenses into potential avenues of attack. The Swedish strategy, meticulously formulated for the predawn hours of 11 February 1659, was multi-pronged, designed to overwhelm the Danish defenses through sheer numerical superiority and the element of surprise.

Swedish forces were divided into several formidable assault columns, tasked with attacking different sectors of the city's extensive fortifications. Key targets included the city's eastern and western gates (like Østerport and Vesterport), as well as breaching points along the frozen harbor and outer ramparts. The plan relied heavily on the element of surprise and the speed of their advance across the ice, hoping to breach the walls before the defenders could fully organize their resistance. Specialized units were equipped with scaling ladders, grappling hooks, and tools specifically designed to overcome the formidable earthworks, palisades, and bastions.

Copenhagen's Unyielding Spirit: The Danish Defense

Despite the formidable threat of a large-scale Swedish assault, Copenhagen's defenders were far from unprepared. Under the direct and inspiring leadership of King Frederick III, who famously declared, "I will die in my nest," the city's garrison, comprised of professional soldiers, was significantly augmented by a passionate and remarkably well-organized citizen militia. University students, craftsmen, and even women and children contributed to the defense efforts, reinforcing the ramparts and preparing ammunition. The city's extensive fortifications, continuously strengthened during the siege, were manned round-the-clock, with a robust network of lookouts and alarm systems.

Crucially, the Danes had keenly anticipated a potential assault across the ice-bound waters. They had taken proactive and ingenious measures, including systematically breaching the ice in strategic locations outside the city walls. This created dangerous moats of open, frigid water, effectively turning the seemingly solid frozen surface into a deadly trap for the advancing Swedish infantry. Furthermore, they had deployed numerous cannons, loaded with devastating grapeshot and chain shot, strategically positioned to rake the open ice approaches with overwhelming fire, making any charge across the frozen surface incredibly perilous and costly.

The Battle Unfolds: A Night of Fierce Combat and Decisive Repulsion

As the Swedish forces launched their full-scale assault in the early hours of 11 February, they were met with immediate, fierce, and utterly determined resistance. The pre-emptive ice breaches proved incredibly effective, as many Swedish soldiers, unaware of the hidden dangers, plunged into the frigid waters, drowning or succumbing to hypothermia. Those who managed to reach the ramparts faced a relentless hail of musket fire, devastating artillery bombardment, and brutal close-quarters combat against a highly motivated and well-prepared Danish defense.

• **Eastern Front (Østerport and Christianhavn):** Swedish attempts to breach these vital eastern sectors were repelled with particularly heavy losses, as defenders unleashed concentrated fire from artillery and small arms from well-fortified positions.
• **Western Front (Vesterport and Kalvebodernes Skans):** Similar fierce fighting characterized the western approaches. The defenders here, including many of Copenhagen's burghers and guildsmen, fought with exceptional bravery and tenacity, often engaging the Swedes in desperate hand-to-hand combat amidst the snow and ice-covered defenses.
• **The Ramparts and Fortifications:** Wherever the Swedes managed to temporarily gain a foothold on the outer defenses, they were quickly counter-attacked and pushed back by fresh Danish reserves. The coordinated defense, combined with the city's formidable engineering and the sheer resolve of its inhabitants, proved insurmountable.

By dawn, the scale of the Swedish failure became painfully clear. Their losses were catastrophic, estimated to be between 2,000 and 6,000 killed, wounded, or captured. In stark contrast, Danish casualties were remarkably low, numbering only in the hundreds. The Swedish king, observing the carnage from a distance, was ultimately forced to order a full and humiliating retreat, signaling the failure of his ambitious plan.

The Turning Point: Why the Battle of Copenhagen Mattered

The failed **Assault on Copenhagen** was a decisive turning point in the **Second Northern War**. It shattered King Charles X Gustav's grand ambition of conquering Denmark and establishing complete Swedish hegemony over the Baltic Sea. The resounding Danish victory not only saved Copenhagen but also effectively secured the continued existence of the Danish monarchy and its independence.

• **Preservation of Danish Sovereignty:** The successful defense prevented Denmark from being absorbed into the Swedish Empire, preserving its identity as an independent nation and a key player in Nordic affairs.
• **Shift in Naval Power Dynamics:** The continued Danish and Dutch control of the Øresund meant Sweden could not fully isolate Denmark, nor could it easily transport troops and supplies without risking naval interception, which significantly hampered Swedish strategic options.
• **Strategic Stalemate and Exhaustion:** The defeat forced the Swedes to abandon their direct assault strategy and maintain the costly and resource-intensive siege, which continued for several more months but without any serious hope of success. This prolonged engagement further drained Swedish manpower and finances.
• **Impact on the War's Conclusion:** The failure at Copenhagen, combined with increasing diplomatic and military pressure from other European powers, ultimately led to a more balanced peace settlement. The war concluded with the Treaty of Copenhagen in 1660, which largely restored the pre-war territorial balance between Denmark and Sweden, although Denmark did permanently lose its eastern provinces (Skåne, Halland, and Blekinge) to Sweden, as had been agreed in the earlier and more punitive Treaty of Roskilde.

Frequently Asked Questions About the Battle of Copenhagen (1659)

What was the main objective of the Swedish attack on Copenhagen in 1659?

The primary objective for King Charles X Gustav of Sweden was to capture Copenhagen, the capital of Denmark, and effectively eliminate Denmark as an independent kingdom. This would have secured Swedish dominance over the vital Baltic Sea region.

Who led the defense of Copenhagen against the Swedish assault?

The defense of Copenhagen was courageously led by King Frederick III of Denmark-Norway, who remained steadfast within the city throughout the siege and battle. He successfully rallied professional soldiers, a robust citizen militia, university students, and the general populace in a combined and highly effective defense effort.

How did the severe winter conditions influence the Battle of Copenhagen?

The unusually harsh winter of 1658-1659 froze the waters around Copenhagen, including parts of the Øresund. While this allowed the Swedish army to attempt an assault across the ice, the Danish defenders cleverly used this to their advantage by strategically breaching the ice to create deadly moats and traps for the advancing Swedish forces, turning a potential weakness into a strength.

What was the ultimate outcome and significance of the Battle of Copenhagen on 11 February 1659?

The battle resulted in a decisive Danish victory, with the Swedish assault being repelled with very heavy casualties. This failure prevented the fall of Copenhagen, preserved Danish sovereignty and independence, and marked a critical turning point that ultimately led to the conclusion of the Second Northern War, albeit with some permanent territorial losses for Denmark.