Family disputes soon destroyed the unity of policy of the Capetian house.  Philip III., well meaning but weak, was drifting into complete dependence on Charles of Anjou, whom Edward distrusted, alike as the protector of the murderers of Henry of Almaine and as the supplanter of his mother in the Provencal heritage.  Margaret of Provence, the widow of St. Louis, had a common grievance with Edward and his mother against Charles of Anjou.  She hated him the more inasmuch as he was depriving her of all influence over her son, King Philip.  It was easy in such circumstances for the two widowed queens of France and England to form grandiose schemes for ousting Charles from Provence.  Rudolf lent himself to their plans by investing Margaret with the county.  Edward’s filial piety and political interests made him a willing partner in these designs.  In 1278 he betrothed his daughter Joan of Acre to Hartmann, the son of the King of the Romans.  The plan of Edward and Rudolf was to revive in some fashion the kingdom of Arles[1] in favour of the young couple.  Though Rudolf was unfaithful to this policy, and abandoned the proposed English marriage in favour of a match between his daughter and the son of the King of Sicily, the two queens persisted in their plans, and new combinations against Charles and Philip for some years threatened the peace of Europe.

    [1] Fournier’s Le Royaume d’Arles et de Vienne (1891) gives
    the best modern account of Edward’s relations to the Middle
    Kingdom.

It is unlikely that Edward hoped for serious results from schemes so incoherent and backed with such slender resources.  Besides his alliance with the emperor, he strove to injure the French king by establishing close relations with his brother-in-law, Alfonso of Castile, who since 1276 was at war with the French.  Earlier than this, he made himself the champion of Blanche of Artois, the widow of Henry III. of Navarre and Champagne.  He wished that Joan, their only child, should bring her father’s lands to one of his own sons, and, though disappointed in this ambition, he managed to marry his younger brother, Edmund of Lancaster, to Blanche.  Though the French took possession of Navarre, whereby they alike threatened Gascony and Castile, they suffered Blanche to rule in Champagne in her daughter’s name, and Edmund was associated with her in the government of that county.  The tenure of a great French fief by the brother of the English king was a fresh security against the aggressions of the kings of France and Sicily.  It probably facilitated the conclusion of the long negotiations as to the interpretation of the treaty of Paris, and the partition of the inheritance of Alfonse of Poitiers.  Edward’s position against France was further strengthened in 1279 by the death of his wife’s mother, Joan of Castile, the widow of Ferdinand the Saint and the stepmother of Alfonso the Wise, whereupon he took possession of Ponthieu in Eleanor’s name.  Scarcely had he established