Irish Empire Flag

The Irish Empire was a large monarchy consisting of the Kingdoms of Ireland, Wales, Brittany, Tunis and Alexandria. It collapsed in 1109, with the death of Bressal Ui Mordha.

Emperors of Ireland

Murchaid Ui Mordha, also known as Murchaid the Conqueror

Donnchad Ui Mordha, also known as Donnchad the Pious

Bressal Ui Mordha, also known as Bressal the Mad and Bressal the Great.



  • Duchy of Leinster
  • Duchy of Connacht
  • Duchy of Ulster
  • Duchy of Meath
  • Duchy of Munster


* Duchy of Brittany


  • Duchy of Gwynnead
  • Duchy of Deheubarth


  • Duchy of Alexandria
  • Duchy of Tunis


Duchy of Leinster

The origins of the Ui Mordha line appear in the Duchy of Leinster. Murchaid Ui Mordha's father had conquered Ulster in the War of the Harp, although the County of Tir Eoghain remained independent. The Duchy at the time was extremely poor. Murchaid's father could not even afford a court education for his son, and instead sent him to be educated in the military.

Irish Unification Wars

When Murchaid returned from the army, he served as count of Dublin. With the death of his father in 1068, Murchaid became Duke of Leinster.

Murchaid almost immediately declared war on the County of Tir Eoghain, which he saw as rightfully a part of Leinster. The Twelve Days War, so named because of Leinster's startling military success, ended in victory for Murchaid. Murchaid then assumed the tile of Duke of Ulster.

Murchaid then sailed across the Celtic Sea to Wales, where the Duchy of Leinster became involved in the War of Welsh Aggression. This secured the Duchy of Leinster an alliance with both the Kingdom of Denmark and the Duchy of Gwynnead. Around this time, Murchaid arranged for his son Donnchad to be married to the daughter of Charles Duke of Brittany.

Returning from Wales in 1074, Murchaid declared war on the County of Mide. The War in Mide ended in 1075 with Murchaid victorious, allowing him to claim the title of Duke of Meath. The remaining independent territories in Ireland, the Duchy of Munster and the Duchy of Connacht, swore fealty to Murchaid, and he was proclaimed the first King of Ireland.

Pax Hibernia

In 1087, Charles of Brittany swore fealty to Murchaid and became a vassal of the Kingdom of Ireland. This was the first territory the Irish would occupy outside Ireland, and was one of their fellow Celtic nations.

In 1089, Ireland again supported Wales in the War of Deheubarth Succession. The outcome of this was was the immediate vassalization of the Duchy of Deheubarth. The following year, the Duchy of Gwynnead swore fealty to Murchaid. Murchaid was declared King of Wales, and the Irish Empire was born.

In 1090, the pope declared the First Crusade to retake Alexandria from the Muslim Kingdom of the Fatimids. Murchaid led the Irish army to capture Alexandria, although the Kingdom of the Fatimids was occupied fighting the Byzantines and the Germans in lower Egypt. When the crusade ended in 1093, the Irish kept the territory, transforming it into the Duchy of Alexandria.

Murchaid passed away in the spring of 1094. His son, Donnchad, became the new Emperor of Ireland. Donnchad was a brilliant tactician like his father, and had also be raised in the military. After a five year period to refill the royal treasury and ensure the loyalty of his vassals, Donnchad embarked on the War in Libya, managing to conquer the whole of it by 1100.

The pope declared the Second Crusade in 1101, to retake Tunis. The Irish armies, fresh from Libya, where among the first Europeans to reach the battlefield, and took the majority of Tunis. By 1103, the second crusade was over, and Donnchad of Ireland was crowned King of Tunis.

Civil War and Decline

In 1119, Donnchad passed away of Pneumonia. Within hours of his death, his youngest son, who Donnchad had intended to rule after his death, disappeared. The only remaining prince, Bressal, was thus crowned Emperor of Ireland.

Bressal showed signs of madness early in his reign, which alienate many of his vassals. After squandering the royal treasury, Bressal embarked on the Third Crusade to retake Jerusalem. Although initially successfuly, Bressal's incompetence soon left his armies crushed and scattered, as the Muslims retook the city. Another Muslim attack retook Alexandria. Bressal, lacking the skill of his father, sued for peace.

The vassals of the Irish Empire, already disillusioned with Bressal, had lost all belief in his ability and right to rule. The Duchy of Ulster declared independence, and proceeded to besiege Dublin. Seizing the opportunity, the Duchy of Gwynnead and the Duchy of Deheubarth succeeded, and became the Kingdom of Wales

Bressal initially managed to beat back Ulster, but relied to heavily on armies originally owned by his former vassals. Eventually, after Bressal again assumed direct command and suffer a crushing defeat in Dublin, the Duchy of Connacht switched sides. With the former Duchy of Leinster subdued, the newly declared Kingdom of Ireland marched on Munster, which surrendered within the next year. Bressal, despite being adored outside his borders, was executed and his body mutilated.

The only loyal Irish Vassals, the Duchy of Tunis and the Duchy of Brittany, had no ties to one another. Charles II of Brittany declared the Kingdom of Brittany in 1127, immediately after the death of Bressal. In 1128, the Duchy of Tunis followed, becoming the Kingdom of Tunis.

The Empire had forever changed the Celtic nations.