The War for Control of Ireland
Ulster had long been the dominant power in Ireland, ever since the duchy acquired Dublin. But despite this, they failed to ever take control in southern Ireland. So they left open the possibility of another power conquering the South and contesting their dominance over the island. With the Western Isles in charge of South and Central Ireland, Ulster was in danger, but they were relying on their most steadfast ally, the duchy of Gwynedd, to defend against the Crovans. But Ulster had something to worry about: the last time the two powers warred, Ulster only survived because of the Seljuk threat. Also, this time, Ulster had no foreign lands to regroup from.
But the numbers and the opinion of many said that the Western Isles were no threat, having only fought the weaker southern powers in Ireland. Dublin alone was more populous than much of the south. On paper, Ulster and Gwynedd together could muster roughly twenty thousand troops, while the Western Isles could only raise half that. Marshal of the Isles Magnus Crovan, uncle of the young Duke Gudmund, had a plan. He sought a lightning quick assault on Dublin and Tir Eoghain, before Gwynedd could have much of an impact. Shrewsbury was at risk, being so close to the Welsh duchy, but Magnus was not worried about that. With Ulster knocked quickly out of the war, Magnus hoped to turn to Gwynedd and either defeat them or negotiate a peace.
Key to this, was the ability of Isles forces to overwhelm Dublin and Tir Eoghain's defenders. Once again, forces on paper said bad things about the success of this plan, but Magnus pushed hard for it, and Gudmund agreed, though he didn't understand the seriousness of the coming campaign. Defeat would mean setbacks in Ireland and England, victory would lead to supremacy in Ireland.
With the campaign approved, Magnus began mustering his forces in fall of 1230. He called for the mobilization of all armies available to the duchy. He sought approval to hire mercenaries as funds allowed, and he gathered the Irish regiments together to form his first army in Osraige. Tuadmumu and Mar both refused to send their troops, but the rest of the vassals agreed to mobilize.
When all the regiments arrived in Osraige, Gudmund declared war, though once again, Magnus did most of the work and was effectively a regent, sending the declaration with his nephew's signature. In early Spring of 1231, Magnus' army of 8500 entered Dublin, which was defended by less than half that number. Magnus won the day, and begin the siege of Dublin in earnest. Meanwhile, Gwynedd, which had declared war in support of their ally, attacking defenseless Shrewbury with 5500 troops. The English county which had become Crovan under peculiar circumstances would not last long against such a force.
Dublin raised forces from its vassals and prepared to defend Tir Eoghain. Only a few minor skirmishes were fought in Dublin after the first battle there, and the siege of Dublin was drawing to its conclusion.
In early April, just before the fall of Dublin, the Dead Oaks company arrived in Sutherland and was hired to support the war efforts. It didn't take long for Dublin to fall, and by mid-April, Magnus was ready to march on Tir Eoghain, knowing he only needed to take one more county to end the war with Ulster. The Irish power intended to prevent that, but numbers on paper proved to be out of touch with reality. With the Dublin Regiment's crushing defeat, Ulster had only 2600 troops to defend with. While Magnus still had around 8000.
Despite this, the battle of Tir Eoghain was quite spirited. The soldiers of Ulster knew Tir Eoghain well, and were able to pick the time and place of battle. Magnus' renown as a general was considerable, but Marshal Staden of Ulster would prove to be the better at Eoghain. Staden's forces seemed almost magical as they danced around the more numerous islanders. Despite being outnumbered three to one, Staden nearly routed Magnus' forces. It was only by sheer numbers that Magnus at last turned the battle around, sacrificing large numbers in a brute force charge that left the battlefield littered with corpses. Magnus had lost 6000 soldiers leaving 2200, while Staden had only lost 1500.
The men of the Dead Oaks company were to save the day, arriving soon after the battle to augment Magnus' siege force. The besiegers feared the arrival of forces from Gwynedd, an event which never happened. Gwynedd focused on conquering Shrewsbury, and the county thus proved to be an unplanned trap for the Welshmen. After conquering Shrewsbury, they headed to Urmumu. But they were too late, as Tir Eoghain fell, and the two counties went to Duke Gudmund. Gwynedd was alone now, but they had no intentions of giving up or changing course. They kept to the same plan, quickly conquering Urmumu.
But Magnus headed to England, to retake Shrewsbury and conquer the one-province duchy. Gwynedd returned its forces to Wales, and met the arriving forces of the Western Isles at Chester. The battle would have been decisive, if only it had been fought. After peace was reached with the Duchy of Ulster (which remained in power in Tir Connail, with a few vassals still), Magnus had sent an offer of peace to Gwynedd. It was refused. But before the battle at Chester could begin, the Duke of Gwynedd asked to speak with Magnus under white flag. The two dukes hammered out an agreement that would cost the Isles 407 ducats. Magnus knew Dublin and Tir Eoghain were worth that price anyday.
Meanwhile, Gudmund was growing up fast in Sutherland. Many at court saw great potential in the Duke who only ruled because of his sickly elder brother's death. Better than his father's jealousy and his brother's weakness, Gudmund already had plans, even at 10. It would soon be time for Magnus to step down and let the Duke take over. Gudmund's lands made him a mighty duke, perhaps even on the precipice of being the first King of the Western Isles. But there was time to wait, prematurely declaring a new kingdom would be likely to ruffle some feathers.
[One county short of being able to create King of Ireland.]