In the months to follow, Tyrone's army and navy licked their wounds in grim anticipation, for though they scored a great victory against two rival Irish Kingdoms and the traitorous Scottish navy, they paid a heavy price(the Navy paying a heavier one) and even with an alliance with France, there was no guarantee England or traitorous Scotland would seize the chance to pounce on the beleaguered growing Irish Kingdom whilst they had the chance, and King Cathal knew it.
Using this period of peace as an opportunity, he ordered the army to be strengthened by another five regiments of one thousand men each, and for another three barques and two transports to be added to his navy, uncaring about the financial costs even as his treasury's funds were stretched to the limit. He also sent a diplomat to Munster, with the request of peaceful annexation of the small province under his banner to unite against the English.
To his pleasant surprise, the King of Munster readily accepted; with his wife unable to procure an heir, Munster's King decided it better to entrust rule of his province to the O'neil Dynasty.
Soon afterward, his diplomat returned from the Papal State, with great news; the Pope had granted Cathal's plans for a united Ireland legitimacy, allowing the Irish King to carry out his plans without risk of backlash.
With nearly the whole of Ireland secure, the blessing of the Pope, and his renewed forces ready to strike, he and his advisors formulated a plan on how to best take the English by surprise, and secure an overall victory against the Wancester Dynasty. Before this, he had sent a request to France beforehand to ask for their aid in the coming war against the English. To his disappointment, France declined, the reason being that the Irish were more than capable of taking care of this matter themselves.
Unable to count on France's aid, Cathal elected to go against the English alone. He also ensured that a sizeable portion of his navy and ground forces were stationed at home, in preparation for the likely scenario Scotland were to betray them once again.
Later at night, his forces stealthily crossed the river under the cover of darkness, and bypassing the English navy at the Irish Sea by taking a detour, they made landfall at the western coast of England. There, they made a daring surprise attack on the English capital of London, where King Henry III resided.
The English defenders were completely taken by surprise; lacking any semblance of order, the battle of London became a complete rout for the English, and King Henry III was unable to escape capture at the hands of the Irish army. By daybreak, the remaining Irish forces at Ireland conquered the Irish province under English control, and King Henry III, along with his family and relatives, were ungracefully deposed from their position as the Royal Family of England.
Without a legitimate heir to take the English throne, England was forced to submit to its rightful conqueror.
Then, on 20th February 1461, Cathal's suspicions came true; Scotland betrayed them once again, as the Scottish Navy engaged the Irish Navy at the Irish Sea. Both sides suffered heavy casualties, but miraculously, the Irish Navy, beleaguered as it was, emerged victorious.
Infuriated at Scotland's second betrayal, Cathal gave an order for his forces to converge on the Scottish Highlands. At that moment, France decided to intervene, and entered the war as an ally of Ireland.
Aghast at the alliance between Cathal's forces and the French, the Scottish were unable to withstand the combined assault of the alliance for long. By the end of August, the entirety of the Scottish Highlands was completely annexed by Ireland, placing the whole of Britannia under Irish control.
With this triumph, King Cathal proudly declared that the Kingdom of Ireland would never falter under the harsh duress of its enemies, so long as its people remained united and determined.
Yet even after the conclusion of the English-Scottish-Irish war, Cathal knew there was much to be done; strengthening of the army and navy, rebuilding of infrastructure, and the integrating of the newly-conquered lands under the Irish banner.
With his finances at rock bottom, Cathal willingly took loans from the banks to fufill these tasks in order to rebuild the damage the war wrought on Britannia, and spent the rest of his reign overseeing the reconstruction efforts.
At the end of his life, on the 30th June 1491, after fifty-four years of blessed life, King Cathal, Unifier of Ireland and Conqueror of Britannia, passed peacefully in his sleep. His son, Eoghan, took the throne, and would soon imprint his name in the annals of history.