 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.