With the death of King Robert, first of his name, the ascension of Joffrey, first of his name, to the Iron Throne of Westeros, and the imprisonment and subsequent execution of Eddard Stark, Lord of Winterfell, Warden of the North and Hand of the King, war has broken out in the Seven Kingdoms.
As a result of Eddard's imprisonment, his eldest true born son, Robb, has called his father's banners to march on Winterfell. Joffrey's unmeditated decision to execute Lord Stark eliminated any hope of a peaceful solution. Had a solution such as this been reached, war would still have occurred, however. Due to evidence uncovered by Stannis Baratheon and the deceased Jon Arryn casting doubt onto the validity of King Joffrey's birth, Stannis Baratheon retreated to Dragonstone to muster his forces. After being rebuffed by Lord Stark, Renly did the same. Although this discovery would technically make Stannis the rightful heir, Renly has done this for his own claim to the throne.
As the new Lord Stark gathered his forces, the Tullies were beset by Lannister forces and completely obliterated. Greatjon Umber repelled enemy forces from White Harbor and took seat as Governer there. Lord Roose Bolton took a lion's share of forces south to blaze a trail. He won several crushing victories, claiming numerous cities and castles including Fairfield and Harrenhal. In a field skirmish, his forces rode down and slew Tyrion Lannister, who was found vulnerable, most likely caught in the crossfire moving between Lannister territories at the time of the invasion.
Roose Bolton took seat in Harrenhal and sent forces west to capture settlements controlled by forces that had rebelled against the Lannisters. It was around this time that tensions gradually began building between the Starks and the Arryns, most likely due to Lysa Arryn (formerly of house Tully). She reacted negatively to Stark requests that the Arryns assist in the war, and most likely placed blame on the Starks for House Tully's sudden destruction. The Tully's primary seat, Riverrun, was at this point home to a huge Lannister garrison. The last in the midlands in and around the Trident. Under orders from lord Stark, Captain Ronnel began a siege, which caused numerous Lannister generals, such as Jaime Lannister, Stafford Lannister, Lancel Lannister, and Lord Tywin himself to disperse from their positions outside its walls.
Around this time, Theon Greyjoy landed on the North West shores. Having only been given a token force by his father, and with the Greyjoy house all together poor, he opened trade relations with the Starks. Stark diplomats easily also formed an alliance with Stannis, who was struggling to rally troops, as many Baratheon bannermen were instead joining Renly's forces.
At this point, Robb Stark had begun journeying south with a small army, to join it to the larger force laying seige to Riverrun. On the way, he intercepted Tywin Lannister. Tywin put up a much better fight than anticipated, having joined with a hidden Lannister army. These men were crushingly defeated, but Tywin evaded Robb's grasp. As a consolation prize, however, Robb soon ambushed Tywin's brother, Stafford. Stafford had not been able to take control of Lannister troops and his guard were caught in the open. He, himself took a sword through the back from Lord Robb whilst attempting to flee.
From there, Robb joined his men to the siege force, giving him in total, slightly more men than the large garrison contained within Riverrun. He took an effective victory, and took numerous prisoners. As with all previous ransoms offered, the Lannisters declined, and Robb executed them. Robb chased Tywin Lannister once again. Once again, Tywin utilized hidden Lannister forces. Once again Robb triumphed, killing them to a man. That man was Tywin himself, who barely managed to evade Robb's cavalry and escape.
Robb stayed in Riverrun for a short while before moving North East. He was near a small force of Arryn soldiers when the Arryns declared war and assaulted him. He and his guard managed to escape, but the battalions of men at arms accompanying Robb were slain by their larger foe. Nonetheless, it was Robb's decision that he would persevere and attempt to attain a ceasefire and from there, an alliance with the Arryns due to their pre-existing ties. He accepted, however that their recent success against him had likely made Lysa confident and eager to continue. He elected to bloody them before offering peace. The Stark/Arryn war did not start up properly for some time, as the Arryn forces were cautious of the larger and more experienced Stark forces, and as Robb had devoted most of his effort to flushing out Lannister rebels from the surrounding area.
Eventually, the war did continue. Robb and Roose each won a number of victories, often with half as many men as the Arryns, who had worked hard levying and training troops while Robb battled ex-Lannister forces. During this time, Bran and Rickon Stark journeyed south from Winterfell, after having funneled small doses of reinforcements for some time. Their troops pushed through rebels, and they took an Arryn town. At this time, they took over four hundred Arryn men prisoner. While Robb was still hoping to bring the Arryns to heel, he could not allow them to regain a large army's worth of men and so ordered them executed. Eventually, the Arryns claimed two minor victories, one against Roose Bolton, and one against Bran and Rickon. In both cases, due to Stark forces finally succumbing to losses sustained in their victories against larger forces. They executed the 21 men captured from Roose Bolton's forces in paltry revenge for the 400 they had lost. Not wanting to start a cycle of revenge, in their next victory, the Starks released 125 Arryn prisoners without ransom. Shortly after this, Robb Stark was declared King in the North.
Presently, the Starks and Arryns are preparing their next moves, due to Robb's first attempt at fixing relations failing. An army serving Joffrey has appeared in the area, and has ousted Stannis' forces in the area, giving the new King in the North yet more to worry about.
