Isabelle Villehardouin

Isabella of Villehardouin (1260/1263 – 23 January 1312) was sovereign princess of Achaia from 1289 to 1307. She was the elder daughter of William II of Villehardouin, Prince of Achaea, and of his third wife Anna, the second daughter of Michael II Komnenos Doukas, the despot of Epiros.

On 28 May 1271 Isabella married Philip of Sicily, son of Charles I of Sicily. This marriage had been pre-determined by the Treaty of Viterbo in May 1267 between Charles, the exiled Baldwin II of Constantinople and Isabella's father. Taking advantage of the precarious situation of the remains of the Latin Empire in the face of renascent Greek power, Charles gained suzerain rights over Achaea; furthermore, the heirs of Baldwin and William were to marry children of Charles, and Charles was to have the reversion of both the Empire and the Principality should the couples have no heirs.

Philip became titular King of Thessalonica in 1274, but he died on 1 January 1277, predeceasing his father. In line with the Treaty, on the death of Isabella's father William, in 1278, it was her father-in-law Charles who succeeded as Prince of Achaea.

Charles died in 1285, to be succeeded by his son Charles II. In 1289, however, on Isabella's marriage to Florent of Hainaut and on Charles II's accession as King of Sicily, he conferred on the couple the titles of Prince and Princess of Achaea, on condition that, if she survived her husband, she would not remarry without Charles II's consent. Florent and Isabella had one daughter, Matilda.

As Prince, Florent negotiated the Treaty of Glarentsa with the Byzantine Empire in 1290. The peace lasted until 1293, when the Greeks retook Kalamata; Florent's emissaries, however, persuaded Andronikos II Palaiologos to return it. In 1296, the Greeks retook the castle of Saint George in Arcadia. Florent laid siege to it, but died in 1298 before it could be taken.

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