Louis of Burgundy

Seal of Louis

Coin of Achaea under Louis

Coat of arms of Louis of Burgundy, prince of Achaea.

Louis of Burgundy (1297 – August 2, 1316), Prince of Achaea and titular King of Thessalonica, was a younger son of Robert II, Duke of Burgundy and Agnes of France.

In 1313, he took part in a complex marriage pact designed to secure control by the Angevins and the Burgundians over Frankish Greece. On July 31, 1313, he married Matilda of Hainaut, heir-general of William II Villehardouin, to whom Philip I of Taranto gave the Principality of Achaea in fief. Louis ceded his claims on the family lands in Burgundy to his elder brother, Hugh V, Duke of Burgundy, who in turn ceded to Louis the title of "King of Thessalonica," which had been sold to their family in 1266. He subsequently did homage to Philip of Taranto, who was suzerain of Achaea and, as titular Latin Emperor jure uxoris, his overlord as King of Thessalonica, and agreed to assist in a campaign to recapture the Latin Empire.

Matilda and Louis arrived separately in Achaea, she sailing directly from Marseille to Navarino with 1,000 troops, while Louis came by way of Venice, where he was soliciting aid from the Republic. Ferdinand of Majorca, who also claimed the principality jure uxoris (his wife Isabelle de Sabran was descended from the younger daughter of William II Villehardouin), had landed there in 1315 and taken to Glarentza. Matilda arrived late in 1315, and several barons, including the count of Cephalonia returned to her allegiance. However, her army was beaten by Ferdinand and his Catalans on February 22, 1316 at Picotin. About this time, Louis arrived, making an unsuccessful attempt to capture the castle of Chalandritsa. Ferdinand sent for aid from the Kingdom of Majorca and the Catalan Company, but neither arrived in time to prevent his death and defeat by Louis at the Battle of Manolada on July 5, 1316. Four weeks later, Louis died. The Chronicle of the Morea attributes his death to a fever, while the Catalan Declaratio summa states that he was poisoned by John, count of Cephalonia. His death left Achaea in an unsettled state, with his brother Eudes, his wife, and the Angevins all attempting to gain it.