The story starts with a family feud. The summer of 1495 CE was not a great summer for King Hans of Denmark, Norway, and Sweden. Although he had ruled in his native Denmark for more than 15 years, it was Sweden, the kingdom in which he had ruled for the shortest period of time, that was giving him major political headaches. Sweden had, for more than 20 years, been effectively ruled by a "regent," Sten Sture the Older, and wanted to break free from the fusion of these three kingdoms, the Kalmar Union.

Sture and the Royal family had history. It was King Hans's father, Christian I (of Denmark, Norway, and Sweden), who had tried to squash the leader of the Swedish separatist movement on the battlefield in the suburbs of Stockholm, in Brunkberg, in 1471 CE. However, Sture, supported by the Swedish peasantry, business sector, and minor nobility, routed the Swedish unionist and Danish forces. This led Sture as Regent of Sweden, a title he would hold twice (from 1471 – 1497 and then later from 1501 – 1503 CE).

So having been the de facto ruler of Sweden for more than two decades by the summer of 1495 CE, Sture had been seriously threatening to finally break Sweden away permanently from the Kalmar Union.

The Kalmar Union

Norway, Sweden, and Denmark can all trace their historical roots back to the so-called "Viking Age." During this time, peoples from Scandinavian societies participated in the widespread trading, raiding, settlement, colonization, and conquest of huge swathes of Europe and beyond. Their presence was felt everywhere, from modern-day Newfoundland in Canada to the Iberia Peninsula, Russia, and even Baghdad. Yet running concurrently with the rise of the Vikings was the long and slow process of the Christianization of Scandinavia.

Starting in the 8th century, this process took over four centuries and saw the evolution of Scandinavia, from a series of petty kingdoms into the medieval kingdoms of Denmark, Norway, and Sweden. These three kingdoms established their own archdioceses in 1104, 1154, and 1164 CE, respectively, thereby integrating into the broader European Christian landscape.

By the 12th century CE, Norway, Denmark, and Sweden all had a series of pilgrim routes, cathedrals, and local saints, along with a burgeoning Church infrastructure. Each kingdom seemed secure, prosperous, and on the road to growing political influence and power… until the arrival into Scandinavia of the bacteria Yersinia pestis, the cause of the "Black Death."

Political weakening and the Kalmar Union

This bacterium caused the bubonic plague, which was mainly spread by infected fleas from small animals, like rodents. Arriving in Europe, from Central Asia, in 1347 CE, it remains the most fatal pandemic recorded in human history. It reached Norway in 1349, with Sweden and Denmark following a year later, and led to widespread death and famine, resulting in as much as a 40% population decrease in Scandinavia. This left the three Scandinavia kingdoms fundamentally weakened.

Adding to a low population base – which already had a devastating impact on each kingdom's economy – was the rising influence of the Hanseatic League. What had started as a series of small confederations of north German trading towns had grown, by the late 14th century, to 200 settlements from the Netherlands to Estonia, from Poland to Russia. The League had a virtual monopoly on maritime trade in the North and Baltic Seas, which had traditionally been plied by merchants from the three Scandinavian kingdoms.

By the late 14th century, the Scandinavian aristocracy wanted to counter the growing political and commercial influence of the Hanseatic League and had the perfect supporter in Queen Margaret I of Denmark. A series of marriages and familial connections between the various royal families of the three kingdoms saw Margaret's heir, Eric of Pomerania, uniting the three kingdoms as a personal union when he was crowned at Kalmar in 1397.

A rough flat map of the Kalmar Union (1397-1523) in black and white. Illustration: vectorissimo / Shutterstock

Setting sail

Despite the union, the three realms were legally separate states, but a common monarch decided their domestic and foreign policy. Over the course of the next hundred years, the largest, richest, and most powerful of the three realms, Sweden, was beginning to get fed up. Diverging Swedish commercial and political interests saw rebellions occur throughout the 15th century, of which Sten Sture's rebellion in May 1471 CE was just the latest.

Since that victory at Bruckenberg, Sture had ruled over the Swedish nation as a protector. Yet by 1495 CE, King Hans was fed up. The Kalmar Union had seen tremendous economic benefits for the Danish crown allowing the construction of a navy. Pride of place was the flagship, Gribshunden (the Griffin). 

Constructed in 1486 CE, this saw a synthesis of Viking-era "clinker" methods and a newer "carvel" construction favored by shipbuilders in southern Europe. The result was a magnificent 115-foot (35 meters) long ship replete with 11 iron cannons and room for over 150 soldiers. It was quite literally a floating castle, and with King Hans on board to sail to Sweden to meet Sten Sture, it was quite possible history's first case of "gunboat diplomacy."

A bad summer just got worse

King Hans set sail, from Copenhagen, aboard his flagship in June 1495 CE.

He was to meet Sten Sture at a political summit to try and bring Sweden back into the fold of the Kalmar Union under his rule. Hans wanted to impress and wow the Swedish nobleman waiting for his arrival, so he loaded the ship's hold with extravagant and rich food and drinks. Furthermore, on board were members of the royal court as well as the King's personal astrologer/astronomer.

The Gribshunden took on supplies in the then Danish port of Ronneby (now in the Swedish province of Skåne) sometime around midsummer 1495 CE. If we are to believe the contemporary chronicle, the King disembarked the ship due to a prophetic message from his astronomer. 

Nevertheless, having taken on supplies in Ronneby, the ship anchored nearby at Störa Ekon, an island nearby. Whilst there, some gunpowder accidentally caught fire, and the ensuing blaze not only sunk the ship but also caused the death of a number of members of the Danish Royal Court. The ship then sunk to the bottom of the Baltic Sea. King Hans's summer went from bad to worse.

In the recent excavation of the shipwreck, sediment and wood samples have been collected, and metal detection has been performed. Photo: Brett Seymour

Discovered by divers, now undergoing a new investigation

During the 1970s, a local Swedish diving club came across the largely intact wreck of the Gribshunden. However, it wasn't until the early 2000s that the first archaeological excavation was carried out. Yet it is the most recent study, carried out with the help of the Viking Ship Museum in Roskilde, that hopes to reveal the secrets of the best-preserved late medieval warship discovered.

The archaeological investigation, with help from Lund University and the Blekinge Museum, has worked hard to unlock the secrets of the Gribshunden. The recent discovery of a rudder and tiller has given an insight into how this massive flagship was steered. Furthermore, the team has been trying to discover how the ship was constructed. 

The ship's synthesis of Southern and Northern European construction methods is seen as a revolution in shipbuilding for this period. Furthermore, the armory of the ship - it was loaded with as many as 68 guns and 11 iron cannons – foreshadows the type of warship in vogue up until the early 19th century CE.

The team also managed to uncover some of the luxurious items King Hans had taken on board. Artifacts already discovered include a trove of silver coin and treasure, exotic spices (including saffron), and even delicate red and black suede slippers. All of these were to play a part in presenting a royal image and as part of "soft diplomacy."

What happened next?

So as the team supported by the Viking Ship Museum in Roskilde uncovers more information and unlocks more secrets of the Gribshunden, spare a thought for poor old King Hans. 

Despite cheating death by disembarking the ship before it went up in flames, the sinking of his flagship would dent the King's prestige. King Hans eventually made it to Kalmar (the Gribshunden was just one of his 16 ships that set sail for Sweden) but was stood up by Sten Sture. 

The status of the Kalmar Union was left unresolved for the next two years before King Hans finally got his (familial) revenge by defeating Sture at the Battle of Rotebro in 1497 CE.

The fascinating story of the Grisbhunden is very much the story of the evolution of medieval Scandinavia from its Viking era past into the early modern period.

More information on the latest discoveries, by Lund University, of the Gribshunden, can be read here.

For more information on the revolutionary design of the Gribshunden and its impact, visit the Smithsonian website here.

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