It can be said that the need to band together in groups is intrinsic to what makes us human beings. Long before the dawn of civilization, humans gathered together in like-minded groups in order to offer one another protection, defend resources, and share the mental and physical challenges of survival. Forming a cooperative group, or herd, may have been one of the earliest human advancements that would one day lead to the complex societies we live in today. But like today, whenever groups gather, conflict is never far behind.

Warfare, it would seem, was the inevitable result of humans living in groups. When one group had something another needed (or wanted), they sought to take it by force. What started as small skirmishes between tribes eventually grew into major battles between city-states, religions, and eventually, nations. The drive to fight and win wars led to countless technological developments throughout human history, but new and advanced weapons have never been the only element necessary to secure victory in a tribal spat or global conflict. Instead, finding and training the most capable war-fighters has always been a key element influencing who would go home the victor and who wouldn’t make it home at all.

Although modern special operations are, as the phrase implies, very much modern, the roots of America’s most elite war-fighting institutions can be traced back as far as warfare itself. In the Marine Corps, we would often liken the lessons we learned in combat training to those first established by the Spartans. Though our modern lineage might be more comparable to that of the British Royal Marines, our ideological ancestors hailed from another time entirely. The mindset employed by Spartan warriors, perhaps as much as their tactical expertise, set them apart from other militaries of the day—something many could attribute to the Marine Corps of today as well. Similarly, one could draw historical parallels between SOCOM’s specialized units and some of the most impressive, capable, and downright frightening warriors throughout human history.

Viking berserkers, recounted in Norse legend as men who would fight with a fury that seemed inhuman, often chose to forgo the chain mail armor of their day, instead adorning themselves with the pelts of predators such as bears and wolves or, often, wearing nothing at all. The bloodlust demonstrated by berserkers in combat granted them a far-reaching reputation, allowing them to sometimes skip the battle completely and instead simply accept an opponent’s surrender based on nothing more than their presence.