#16
Roughly 50 years before the First Orcish Invasion, there was peace over Azeroth, with but one exception- the Forest Trolls. The Forest Trolls in Azeroth raided convoys and villages frequently (too frequently for the liking of Azeroth's king). The Azerothien King created the an act to put an end to the Troll raids. The act allowed humans to hunt down and kill Trolls. The humans could return Troll heads for a reward from their local lord.The Troll clans in Azeroth at the time were very fragmented, and did not communicate well with each other. Oftentimes they'd actually be at war with each other. The clans at this point though were still generally tight-knit; that is, clan members kept in close contact with each other and followed the orders of their chief. This allowed the Troll Chieftains to meet and discuss the threat this human act posed. They decided to band together and fight the common foe. They named Warlords, who controlled all Troll clans in certain regions, which were divided among 20 Troll warlords. One Chief broke off and carried on his own war after not being chosen as a chieftain.
The Trolls managed to overwhelm the Azerothiens, even with slightly inferior numbers. They breached the outer walls of Stormwind, but never entered the Keep. Instead, they left a small group to siege Stormwind Keep, only allowing food in by air. They thought this might help them somehow later.
The Trolls pushed north into Khaz Modan, where they met heavy resistance by the Dwarves. They were able to recruit the Trolls in their region to join their cause. This enabled them to strike almost from almost anywhere, which contributed greatly to the defeat of the Dwarves. The Trolls quickly pressed north, creating a small, but effective navy along the way. They spread through the entire northern portion of the continent, recruiting Trolls from all over to join their cause and rebel. They even tried to push into the dark lands of Gilneas, but the Dark Mages there had exterminated all species of intelligent life that were not humans (they even exterminated humans that did not join their dark cause). The Elves had many a fierce battle with the Trolls in Quel Thalas as the Troll army from Azeroth reignited the hatred between the two races.
The humans, Elves, and Dwarves eventually pushed back the Trolls. The demise of the Troll army came about because they attempted to spread too quickly, to too many areas in the northern continent. Their excursions into Gilneas and Quel Thalas were two of the most devastating to them. Stromgarde lead the charge to push the Trolls back to Azeroth, where they were placated.
Forest Trolls remained all over the eastern continent of the world of Azeroth, but their once great clans, and fighting force was now gone. They were reduced to living in small groups of 3-5, and offering no threat to any nation. They still raided small human parties, but barely ever villages or convoys. They became but a nuissance.
Not until Zuljin would the Trolls once again come anywhere near to touching the power they once held.