Year 1174 (MCLXXIV) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar, the 1174th year of the Common Era (CE) and Anno Domini (AD) designations, the 174th year of the 2nd millennium, the 74th year of the 12th century, and the 5th year of the 1170s decade. Events By place England July 13 – Battle of Alnwick: King William I (the Lion) supported by Flemish mercenaries invades England to help fight in the baronial rebellion against King Henry II. William attacks Prudhoe Castle in Northumberland, but is unable to capture it. He is captured by Lord Ranulf de Glanvill and brought back to Newcastle. Henry occupies a part of Scotland, with its five strongest castles: Roxburgh, Berwick, Jedburgh, Edinburgh and Stirling. September 5 – Canterbury Cathedral is severely damaged in a fire. September 30 – The Revolt of 1173–1174: After a year and a half of rebellion, Henry II achieves peace agreements with his sons Henry the Young King, Richard, Geoffrey and John at Montlouis, on the basis of the pre-war status quo. Before he returns to Normandy, Henry orders the rebel castles in England and Aquitaine to be destroyed. October – Battle of Thurles: Gaelic-Irish forces under King Domnall Mór Ua Briain defeat an Anglo-Norman invasion at Thurles in Ireland. The English expedition led by Earl Richard de Clare (Strongbow) is surprised while encamped in the area of Lognafola and is forced to retreat to Waterford. December 8 – The Treaty of Falaise: Captured by the English, William I is forced to sign a peace agreement. The treaty makes Scotland a feudal possession of England, William and his nobles swear allegiance to Henry II. He must hand over several castles to Henry in return for his freedom. Europe Summer – French forces under King Louis VII, supported by Henry the Young King and Philip of Alsace, encircle Rouen. The city holds out against the war engines long enough for Henry II to arrive in the middle of August to stage a rescue. The besiegers are fearful that Henry will invade France and the siege is lifted. October 29 – Emperor Frederick I (Barbarossa), on his fifth Italian campaign, begins the siege of Alessandria in northern Italy. He is opposed by the Lombard League (now joined by Venice, Sicily and Constantinople). Levant May 15 – Nur al-Din, Seljuk ruler (atabeg) of Syria,