Humans were not the first creatures on the island of Amia. Amia was inhabited almost exclusively by monstrous races and a small breakaway community of elves who fled their original home to settle Winya long before the first boatloads of human, hin, and dwarf settlers arrived on the Amian coast.
Prehistorians theorize that the orcs who first came to Amia were part of a larger collective of mountain orcs that descended from the Frozenfar and, through constant battles with the denizens of Toril and fractious splintering of their own tribes, spread gradually southwards in increasingly small pocket tribes. Though no map of the Trackless Sea was ever designed at the time, it is assumed (based upon certain historic accounts and contemporary geological trends) that a land bridge extended southwestwards into the Trackless Sea. Very recently, the land bridge theory has been replaced by the notion that there was no solid bridge of land extending into the Trackless Sea but rather a much denser series of islands and landmasses (it is believed that the Moonshaes were three times their size at this period of ancient history, before a rapidly rising sea level buried most of what might have once been a complete landmass into a series of islands).
These early mountain orcs went as far south as the land mass we know today as Amia, but any claims that they traveled further are dubious, as they were not talented shipbuilders in their own right but were capable of constructing small fleets of very unsteady rafts that could carry them at least as far as Amia. Once on Amia, food and territory were plentiful.
The only significant conflict that faced the orcs in these early years were the re'kazan, which is an archaic orcish word meaning "night elf". Though modern prehistorians assert that it was very unlikely that the orcs were faced with a drow community on the island of Amia in these very early times, the elves of Winya insist that there was a rogue drow city living in a dry, hollow bowel on the south part of the Amian landmass, assumed to have been a portion of a pre-existing Underdark that was separated from the rest of the Underdark by the intrusion of seawater.
These transplanted mountain orcs were fighting a war on two fronts - against the elves to their north and the re'kazan to their south. The Winyans, being the only community with a strong enough oral tradition to recall details of the time, claim that the re'kazan inevitably invaded the Frontier caverns where the orcs had made their homes by using underground tunnels and occupied their territory, enslaving the orcs and using them as martial fodder in a heated war of attrition on the village of Winya in the Nexus Falls region. These early battles of Winya are not considered part of the military canon of the Crown Wars as they occurred some time after those events, but recent elven scholars have been suggesting they be included.
The elves eventually earned a victory over the combined forces of the re'kazan and their enslaved orcs, leaving the re'kazan and their limited numbers to face an insurrection by their slaves, who had home field advantage on the surface where they were made to fight.
Very little is known about what became of the orcs who had been enslaved or their re'kazan masters, but the orcs who had settled in the frontier, a hardy and stout race, managed to survive the conflict even with the vast majority of their male warriors removed from the tribe by the re'kazan, never to be heard from again.
Passenger manifests from colonial vessels that settled the Amian coast several hundred years ago indicate that in addition to explorers, wealthy merchants, surveyors and refugees of human, dwarf, and hin stock, there were also a number of orcish slaves brought to Amia. These were gray orc slaves, worshippers of the mighty Gruumsh, slayer of the Mulhorandi god Re during the Orcgate wars. This was a religion altogether unfamiliar to the frontier orcs who had long ago settled the Amian island, but it is speculated that some of these orcish slaves transplanted to Amia during its settlement escaped their masters and brought this very orcicentric faith to the orcs of the frontier.
Although the Frontier Orcs pose a significant threat to merchant caravans that travel close to their territory, these orcs have rarely ever militarized beyond their borders to attack the neighboring settlements of Cordor or Bendir Dale. Adventurers continue to raid their caverns, often in retaliation for their brutal caravan raids that rarely leave anyone alive, or by commission of individual merchants who want their stolen goods returned or by the city of Cordor, who have traditionally encouraged a campaign of consistently controlling the Frontier Orc population through regulated bloodshed.