France was a very decentralised state during the Middle Ages. At the time, Lorraine and Provence were states of the Holy Roman Empire and not a part of France. North of the Loire, the King of France at times fought or allied with one of the great principalities of Normandy, Anjou, Blois-Champagne, Flanders and Burgundy. The duke of Normandy was overlord of the duke of Brittany. South of the Loire were the principalities of Aquitaine, Toulouse and Barcelona. Normandy became the strongest power in the north, while Barcelona became the strongest in the south. The rulers of both fiefs eventually became kings, the former by the conquest of England, and the latter by the succession to Aragon. French suzerainty over Barcelona was only formally relinquished by Saint Louis in 1258.