Sitting in thrones and brokering powerful alliances. Engaging in pomp and circumstance. Conducting pirate raids? One of these things may not seem like the others, but all four were things that would have seemed familiar to Denmark’s earliest kings. Pirates actually founded Denmark according to ScienceNordic’s Stine Rendrup Johansen.

Johansen writes that looting and piracy were the basis of the earliest Danish kings’ power. After all, the years between 800 and 1400 were the time of the Vikings. Medieval historian Thomas Heebøll-Holm tells Johansen that pirate raids weren’t just a method of robbing. They were also a means of “conventional warfare or revenge” for early Danish leaders.

“Essentially, Viking raids between 800 and 1000 CE funded the building of a Danish royal power,” Heebøll-Holm told Johansen. Viking pirates used expeditions and pirate-approved methods to struggle for power, unite their own warriors and fund their ongoing activity, Johansen reports. In the future, Heebøll-Holm hopes to gain a better understanding of just how piracy affected things like laws and norms around the monarchy.

In case you’re still skeptical about the power of the pirate in days of yore, here’s a sobering description of the impact of Viking pirate raids. Stefan Eklöf Amirell and Leos Müller write that Viking pirates acted “as catalysts for political change and dislocation across Europe.” 

In ninth-century England, they write, “every kingdom but one was destroyed  and up to half the country was occupied by Viking forces.” The Kingdom of Frankia had it even worse, they write, with 14 percent of the entire economy surrendered to Vikings. “Whole regions are recorded as ‘laid waste’ and thousands were killed and enslaved.”