 His oldest son, Jean, was betrothed to Philip's daughter Marie, and it was agreed that the Brabançon heir would complete his education at the French court in Paris and that Robert of Artois would be expelled from Brabant.The support of France strengthened John's hand with his feudal suzerain, the Holy Roman Emperor.Though he was technically the Emperor's feudal vassal, John had been able to ignore Emperor Louis IV's summons to join him in his intended invasion of Lombardy (1327).<ref>Boffa 2005