# Siege of Dublin and Castleknock (1171)

URL: https://allhistories.com/ireland/timeline/1171-siege-of-dublin-and-castleknock
Themes: Wars & Battles

Diarmait Mac Murchada died at Ferns in May 1171, and Strongbow claimed the kingship of Leinster in right of his wife Aoife. The Normans' position was precarious: Henry II had cut off supplies and reinforcements, many Leinstermen rejected Strongbow, and the deposed ruler of Dublin, Ascall mac Ragnaill, returned with a fleet from Norway and the Isles. Ascall's assault on the east gate of Dublin was beaten off by Miles de Cogan and his brother Richard, and Ascall was captured and beheaded. Soon afterwards the High King Ruaidrí Ua Conchobair surrounded the city with a great army drawn from Connacht, Bréifne, Airgialla and Leinster, encouraged by Archbishop Lorcán Ua Tuathail, while ships from the Isles blockaded the harbour. After about two months, with food running out, Strongbow's garrison made a surprise sortie and attacked Ruaidrí's camp at Castleknock, routing his army; according to Gerald of Wales the High King himself was caught bathing and narrowly escaped. The victory ended the only serious attempt to drive the invaders out in the first years of the conquest. It confirmed Strongbow's hold on Dublin and Leinster, but also convinced Henry II that he must come to Ireland in person to assert his authority over his over-mighty vassal.

## Why it matters
The defeat of the siege of Dublin secured the Norman conquest of the east and prompted Henry II's intervention.

Ruler at the Time: [Ruaidrí Ua Conchobair](https://allhistories.com/ireland/rulers/ruaidri-ua-conchobair)

## Sources
- [Wikipedia — Siege of Dublin (1171)](https://en.wikipedia.org/wiki/Siege_of_Dublin_(1171))
- [Wikipedia — Diarmait Mac Murchada](https://en.wikipedia.org/wiki/Diarmait_Mac_Murchada)
- [Encyclopaedia Britannica — Ruaidri Ua Conchobair](https://www.britannica.com/search?query=Ruaidri+Ua+Conchobair)
- [Dictionary of Irish Biography — Ruaidrí Ua Conchobair](https://www.dib.ie/search?search_api_fulltext=Ruaidr%C3%AD+Ua+Conchobair)
- [Wikipedia — Norman Ireland (period overview)](https://en.wikipedia.org/wiki/Lordship_of_Ireland)