The 'Seventy-Seven Years War is a conflict between the kingdom of Alionne and the Jheksal Empire. Unsung Story: Tale of the Guardians is set during this war.
The Jheksal Empire’s Bid to Rule the Continent
The following section is a summary written by wikipedia:Yasumi Matsuno:
The Seventy-Seven Years’ War began with the death of King Antoine III in 1204, which left the Alionne throne without an heir. The crown should have passed to King Antoine’s cousin, Reksar VI, who was three years old at the time, but this displeased King Antoine’s uncle, Barvetha II, emperor of Jheksal. He declared war the next year, 1205.
In fact, this was only a pretext to invade Jelamonea, a province of Alionne bordering the Jheksal Empire. Jelamonea was once an independent kingdom, until Alionne invaded a century earlier. Jheksal had been providing clandestine support to insurgents attempting to restore Jelamonea’s independence, but thus far its efforts had amounted to nothing. Unhappy under Alionne rule, the Jelamonea aristocracy and the people at large had long wanted Jheksal to formally intervene.
After declaring war, Barvetha II acted quickly. He dispatched a large force to the Leá Noel, a great river separating the Alionne province of Nionne from Jheksal, and brought the nearby towns under imperial rule. The Leá Noel also served as a vital trade route with the city of Branhom, the royal capital of Alionne. Controlling even a small portion of the river and surrounding lands would give the empire a stranglehold on Alionne commerce. It also meant the empire could land troops in Alionne territory at will. Alionne had no choice but to counter by sending their own forces, and the two armies would engage in countless battles along the river, termed the 1st through 3rd Sunochta Conflicts. (For all practical purposes, the area remained under imperial rule for 37 years until Na’Mor began their invasion from across the sea in 1242.)
Alionne forces landed on the southern coast of the continent and occupied the city of Latzera, situated along the Jakeos Sea. But the city was soon surrounded in a siege that lasted nearly fifty days, and with no path of escape, the Alionne forces dwindled as they were captured or slain in battle. (For sacrificing his life to save his allies from the siege, Vensniel became known as the “Siegebreaker” by friend and foe alike.)
From the outset of the war, Alionne found itself solely on the defensive. Though this was in large part due to the fires of rebellion fanned throughout the kingdom by Jelamonea separatists and the Jheksal Empire, this was by no means the only problem Alionne faced. Many nobility near the Jheksal border considered the possibility of imperial rule as an improvement on their lot and began ignoring Reksar VI’s demands or refusing them outright, becoming a true thorn in the king’s side. All the while, Barvetha II plotted ever thicker with the nobles of Alionne. Those who could be bought with coin, he bought. Those who coveted power, he flattered. Those who had weaknesses, he extorted. Step by cautious step, Barvetha deftly maneuvered to erode the very foundation of Reksar’s power.