In the seventh season of Game of Thrones, Jon Snow is determined to woo Daenerys Targaryen. And we mean "woo" in many senses. Sure, we're low-key hoping they get married (even though they're related), but we're also hoping they join forces to fight off the approaching White Walker army that draws closer with each passing day. In the fourth episode of the season, Jon Snow takes another stab at winning over the Mother of Dragons: he takes her into his newfound dragonglass cave to show her some supercool cave paintings. While the whole affair yielded plenty of hilarious reactions and a flashback to that other cave scene, it also brings to the forefront a group of people we've heard about time and time again: the First Men. According to Jon's sweet new cave doodles, the First Men united with the Children of the Forest to defeat the White Walkers many millennia ago. Wondering about the First Men? So were we.
The First Men got their name after they became the very first humans to migrate to the continent of Westeros from Essos about 12,000 years before the events of Game of Thrones. They crossed to the region on a natural land bridge that connected from Essos and ended somewhere near modern-day Dorne. Up until then, the land of Westeros was ruled by the magical Children of the Forest and the giants. The Children, who were angry about the arrival of the humans, destroyed the land bridge that connected the two continents. For many years, the Children and the First Men battled in a grueling war. The Children were pushed back to the far North. Eventually, they signed a pact that would bring peace between the two groups. The First Men began building their kingdoms across the continent.
During the war, though, the Children of the Forest were desperate. Leaf, one of the Children, tells Bran at the Weirwood Tree that they eventually ended up creating the White Walkers. "We were at war. We were being slaughtered," she says. "Our sacred trees being cut down. We needed to defend ourselves . . . from you. From men." Eventually, though, the White Walkers turned on their makers, which led to the Great War Jon points out in the cave drawings. The White Walker threat was so formidable that the Children and the First Men eventually banded together to fight them off. With extra help from the giants and the Children, Bran the Builder constructed the mighty Wall to keep the White Walkers away, should they ever return. He also built Winterfell, became the first King in the North, and founded the Night's Watch to forever protect Westeros from another invasion.
This is where the Seven Kingdoms come in. Long after this major war with the White Walkers, a race of men known as the Andals sailed across the sea to Westeros. They spread across the continent rapidly and ruthlessly, conquering land as they found it. The one region the Andals were unable to fully overtake was the North, which was fortified strongly against invading forces. Even so, the Andals settled in everywhere else.
Nowadays, there are very few traces left of the First Men, though it's worth noting that the original race's blood runs in all the houses. In the more southern houses, like the Lannisters, the Targaryens, and the Baratheons, the blood of the Andals is way more prominent. They have very little blood from the First Men. The Starks, on the other hand, have a lot more blood from the First Men in their lineage. But the Wildlings that grew up North of the Wall are perhaps the most "pure-blooded." Very few of the Andals, if any, have ventured beyond the Wall. This explains why the Wildlings snub Southerners and are against intermingling.
Now that the White Walkers are coming back, it's time to forge the same union that occurred all those thousands of years ago. Let's just hope all the houses figure their sh*t out in time.