Consolidation of Thierry of Alsace’s Rule and the Flemish Conflict with Liège and Namur (1128 CE)

Following the death of William Clito in July 1128, Thierry of Alsace solidified his claim to Flanders, establishing his government in Ghent. Despite his Imperial-backed victory, Flanders remained unstable, with ongoing conflicts in Liège and Namur.

Godfrey of Leuven’s War Against Liège and Namur

• Godfrey I, Duke of Lower Lorraine, continued his military campaigns against the Prince-Bishopric of Liège and the County of Namur.
• As a key ally of the Capetians, Godfrey had previously supported William Clito’s claim to Flanders and remained opposed to Thierry’s rule.
• His war in the Meuse valley, which had begun before Clito’s death, continued as an independent regional conflict, shaping the balance of power in Lotharingia and northern France.

Thierry of Alsace Secures Power in Flanders

• Thierry established his rule in Ghent, one of the most economically and politically important cities in Flanders.
• He was recognized as Count of Flanders by the major Flemish cities, including Bruges, Lille, and Saint-Omer, confirming his legitimacy.

Anglo-Flemish Relations: Henry I’s Support for Thierry

• King Henry I of England, having previously supported William Clito, now shifted his allegiance to Thierry.
• Henry ordered his Flemish vassals in England to swear fealty to Thierry, reinforcing his political legitimacy and military backing.
• This Anglo-Flemish alliance secured English influence in Flanders, an economically vital trade partner.

Impact and Consequences

• Thierry’s recognition across Flanders marked the end of the immediate succession crisis following Charles the Good’s assassination.
• The continued fighting in Liège and Namur meant that Imperial-backed and Capetian-backed factions remained at odds, fueling ongoing regional instability.
• Henry I’s endorsement further strengthened Anglo-Flemish ties, ensuring that England retained influence over the Flemish trade economy.

Though Thierry had successfully secured his rule, Flanders remained entangled in the broader power struggles of France, the Empire, and England, setting the stage for future political realignments.