Walter VI , Count of Brienne Walter VI of Brienne ( née : Gaulterio de Candia , VI Comte de Brienne , c . 1304 – 19 September 1356 ) was Count of Brienne , Conversano , and Lecce , and titular Duke of Athens . Walter was the son of Walter V , Duke of Athens , and Jeanne de Châtillon ( died 1354 ) , the daughter of the Count of Porcien , Constable to King Philip IV of France . Life . Early life in Italy . As grandson of Hugh of Brienne ( d . 1296 ) , he was heir to a vast property all around the Mediterranean . After his father ' s death at the Battle of Halmyros on 15 March 1311 , Walter became Count of Brienne , etc . , and Duke of Athens . However , all of the Duchy except for Argos and Nauplia in the Principality of Achaea had been overrun by the Catalan Company , and Walter spent much of his life in an unsuccessful struggle to recover that inheritance of his grandmother ' s family , although he spent most of his life in Italy and France and left Argos - Nauplia to be ruled by guardians . The Duchy of Athens was not the first loss in his family : Walter ' s grandfather had been rejected from the succession of the kingdoms of Jerusalem and Cyprus , and his great - great - grandfather had been Pretender of the throne of Sicily , as husband of the sister of William III of Sicily . They had barely regained the County of Lecce , and were still claiming the Principality of Taranto . His mother Jeanne carried out a vigorous struggle against the Catalans during his minority , which , however , had little military effect but impoverished him . To strengthen his position , Walter engaged in a strategic marriage to Margaret , the niece of King Robert of Naples and daughter of Philip I of Taranto by Thamar Angelina Komnene , in December 1325 . At this time , Florence requested King Robert ' s support in protecting Guelph interests in Italy , and elected his son , Charles , Duke of Calabria , as signore of Florence for a ten - year period ( 1326 – 36 ) . Walter VI ' s almost - princely position in the Angevin court soon won him an appointment as Vicar for Charles of Calabria , an office that he only exercised for a few months in 1326 . Greek campaign of 1331 – 32 . In 1329 , Walter obtained the support of Robert of Naples and Pope John XXII , who declared a crusade for his recovery of Athens . Walter sailed for the East in 1331 , but the price of Robert ' s support was that he first reduce the Despotate of Epirus , as Vicar - General of the Latin Empire . Here he took Arta and forced the Despot John I Orsini to acknowledge the suzerainty of Naples . His attempts to recover Athens and Boeotia , however , were frustrated by the Venetian alliance with the Catalans and the refusal of the Catalans to give battle . His only son , Walter , died of illness during the campaign , and he returned to Naples in 1332 . Ruler of Florence . He also occupied himself with his lands in France , and was the King ' s Lieutenant in Thiérache in 1339 . His wife died in 1340 , and he returned to Italy in 1342 when the Florentine ruling class of wealthy merchants called upon him to rule the city . Since 1339 , Florence had been in the grip of a severe economic crisis brought about by immense English debts to Florentine banking houses , and by astronomical public debts incurred in trying to obtain the nearby city of Lucca from its Veronese lord , Martino Della Scala . The Florentine nobility looked to foreign powers to solve the city ' s seemingly impossible financial problems , and found an ally in Walter of Brienne . Although the ruling class invited Walter to rule for a limited time , the lower classes , who were fed up with the ineptitude of Walter ' s predecessors , unexpectedly proclaimed him " signore " for life . Walter VI ruled despotically , ignoring or directly opposing the interests of the very same merchant class that had brought him to power . The " Duke of Athens " imposed harsh economic correctives on the Florentines , including the flat tax " estimo " , and " prestanze " , postponements of the city ' s repayment of loans forced from the wealthier citizens . These measures both angered the Florentines , and helped alleviate the fiscal crisis that had been stewing for years . After only ten months , Walter of Brienne ' s " signoria " was cut short by conspiracy . Walter VI was not only forced to resign from office , but barely escaped Florence with his life . Later life and death . In 1344 he married Jeanne , the daughter of Raoul I of Brienne , Count of Eu . She bore him two daughters , Jeanne and Marguerite , both of whom died young . As he had no surviving children , it was evident that his sister ' s issue would inherit his possessions and claims . He was appointed Constable of France in 1356 and in that capacity died on 19 September 1356 at the Battle of Poitiers . He was succeeded in his titles and pretensions by his sister Isabella and her sons . As he had left Greece , his eldest surviving nephew Sohier d ' Enghien was holding the lordship of Argos and Nauplia . When the inheritance was divided after Walter VI ' s death , Isabella ' s sixth son Guy d ' Enghien received the Greek lordship . Isabella III survived his brother and died 1360 . Her husband Gauthier d ' Enghien had died in 1345 . For a few years , she became Countess of Lecce and Brienne , etc . , as well as titular Duchess of Athens and of other claimed titles . Since her eldest son Gauthier had died before Walter , her heir was her second son Sohier of Enghien . She allowed her inherited lands to be divided between her numerous children during her own lifetime ( see Brienne claim to the Kingdom of Jerusalem for her descendants ) . Cultural legacy . The " Duke of Athens " who appears in the seventh tale of Day Two of the " Decameron " as one of the nine lovers of the Sultan of Babylon ' s daughter , while not historically accurate , is probably a satirical allusion to Walter VI - his brief , but unforgettable dictatorship in Florence occurred less than ten years before the writing of the " Decameron " .