On 12th Petalstorm 2A 5999, the Tiran Parliament voted in favour of declaring war on the growing Imperial Troll Empire. The only opposing vote coming from House Drakenfiend who commended the action as foolish, however a number of normally peaceful voters were absent due to the effects of uncontrolled Spore usage.
In response to the leadership's wishes, the Tiran Military drew up an invasion plan consisting of two parts: first, the rapid capture of the Imperial capital of The Grand City of Mor'Koc which was deemed to be exposed, then second the invasion of the Troll Homelands once sufficient naval support could be gathered. Once approved, the 4th, 5th and 6th legions marched while heavier siege equipment and a smaller shock force was loaded into HMRS Balor Drakenfiend, a large warship which had been seized from House Drakenfiend after their refusal to mobilise their feudal levies.
The plan was to have the forces land further down the coast and march around the city to the South Gate, which their intelligence told them was the least heavily defended. Meanwhile, the Balor Drakenfiend would sail through the Mor Estuary and drop off a number of additional siege weapons and extra support, allowing the army to surround the city. While this plan was functional, the lack of further naval support left it with a noticeable gap in firepower which would only serve to slow them down and increase the risk of something going wrong. Nevertheless the higher-ups decided that the one support ship was sufficient as, in their arrogance, they decided their ground troops would be more than a match for a city so large as they wouldn't be able to defend it all at once.
As the army assembled, landing at the dead of night off the coast of P’Lar and made the long trek up to the city, the Balor Drakenfiend, containing two trebuchets and a number of support personnel and armed with the largest and most powerful ballista Oerth has ever seen, loaded up in the port of Caislean and slowly made its way south. The ship did not get far, as its badly informed crew quickly got lost in the web-like waterways of the Mor Estuary, drifted over the Manzil border and was struck repeatedly by cannon fire from the Mogoi Town Guard, after which it continued, listing heavily, before crashing into the rocks at the entrance to Mor'Koc's North Docks. The surviving crew were quickly captured.
The Tiran army themselves failed to take into account that the open farmland from P'lar up to the city had far more people than they expected. As such, they were quickly spotted by locals who sent the information directly to The Immortal Governor, so by the time the Tiran forces actually arrived at the South Gate the defenders, thanks to the information and the capture of the Balor Drakenfiend, had already know they were coming for some time. The Tiran forces, with their plan in tatters and nowhere left to go, circled the city and hunkered down, firing volleys of catapult and ballista shots over and into the walls. Famously, three ballistae crews tore down the wooden doors of the South Gate with repeated shots, though not quickly enough to prevent the portcullis from closing, meaning they still couldn't enter the city. It was relatively clear from the moment that the trebuchets began firing and found that they couldn't penetrate the stone that it was unlikely that they could deal with a prolonged battle, but the leadership back in Tir refused to back down and let them leave, despite being unprepared and unequipped for a prolonged battle.
Due to this combination of underestimation, arrogance and misfortune, that one-day raid would drag out into a four-month siege which, for the Tiran army, ended in abject failure thanks to the efforts of the now-famous Mor’Koc Militia, who managed to kill or capture every force who attempted to breach the city walls and even managed to capture two trebuchets which now reside in the Imperial Armoury. A major turning point of the battle occurred one month in as the army's Wood Elf soldiers, seeing the multicultural nature of the city and reevaluating their second-class citizen relationship with the High Elf, changed sides and began attacking their own forces, lowering the size of the army by a full third as they took refuge in the city.
The siege was bought to an end by the personal actions of the Governor, himself a Wood Elf who had lived in the city since his boyhood. Capturing the surviving Elven generals, he promised to return their men to Tir if only they would order them to throw down their arms and agree to stay in the city. Unable to watch their men continue throw their lives away, the generals agreed and stacks of Elven bows and swords were piled next to the city gates. Many High Elf soldiers who survived the battle eventually returned to the city as refugees following the war, giving the Greater Mor'Koc area the notable High Elf population it still has to this day.