Vargo's Find

In Vargo the Trollslayer's day, Tarsa was even wilder and more sparsely populated than it is today. A handful of small city-states dotted the region, but many of the Tarsaks  still lived as nomadic hunters following the herds and most of the land was unclaimed by any warlord or tribe. In addition to the human inhabitants, Tarsa was home to dangerous beasts of every description. It was common practice for rulers to offer bounties on monsters who were preying on their people, making monster hunting a lucrative profession for those with the right skills.
Like many of his profession, Vargo the monster hunter gained a reputation as being especially skilled at dispatching a particular kind of beast, in his case Trolls. During one of his hunts, Vargo tracked a small band of trolls to a cave along the seacoast. He found a spot on a nearby hill (most assume this was The Slab) and observed the trolls for several days to get an idea of their routines and make sure he hadn't underestimated their numbers. Noting that the trolls typically left the cave alone or in pairs to forage, hunt, and drink from the river, Vargo spend the next few days locating ambush points and setting up obstacles along the most common routes taken by the trolls.
On the tenth day, Vargo started taking heads. By the mid-afternoon he'd killed 5 trolls, which by his count left only 3 still in the cave. Vargo liked those odds (and knew that it wouldn't be long before the remaining trolls started to wonder what was taking their friends so long to return), so he readied his axe and entered the cave. The element of surprise allowed him to kill the first troll in one stroke. The remaining pair were more challenging to defeat, but Vargo was ultimately victorious.
With the trolls defeated, Vargo went deeper into the cave to check for treasure, human prisoners, or particularly cowardly trolls. He didn't find any of these things, but he did find a section of wall made of cut stone. Although he'd never heard any stories of Eloszorian cities or castles on this part of the coast, the vast wealth that was sure to be found in an unspoiled ruin were enough to guarantee Vargo's return.
After collecting his bounty, Vargo spent a few months securing the services of a small band of partners in whose skills and character he was confident and discreetly gathering supplies in a way that avoided large purchases that might encourage gossip. Once he had everything he needed, Vargo led his associates out of town in the dead of night and returned to the troll's cave. After ensuring that no new creatures had moved in, they started digging.
The explorers made it through the rough wall at the back of the cave with no problems, but quickly realized that they didn't have the equipment or the manpower to excavate a structure buried under the detritus of a few dozen centuries. They decided to excavate what they could in hopes of finding something of value that could fund more exploration. Fate was on their side. Two weeks into the operation, they discovered what appeared to be a shrine of some sort that contained a golden idol worth enough to fund a second phase of excavation.
Since the sheer scale of the work force required to continue exploring the city--which Vargo named Tir Vagyon, ("City of Fortune")--negated any chance of secrecy, Vargo's second round of hires included a small force of mercenaries to defend his claim. The dig continued for the rest of Vargo's life and for several generations thereafter (after which the cave was sealed). The encampment that grew up around the exploration of the ruins became known as Vargo's Hill, ("Kosz Vargo)" which through the vagaries of linguistics eventually became "Khezvaros."