Philip IV needed a big income for his Kingdom. First, because of the war against Flanders and England; and second because he had some tentatives of power centralization that required a significant amount of money. As a way to finance his expenses, Philip IV issued many gold and silver coins; in fact, he was the first French king to issue gold coins for circulation. For this reason, he is known as “le roi aux monnayeur” (“the King made minter”). Here and here you can find more information.
Regarding the masse d’or, they were issued between 1296 and 1310. In that time France was fighting against Flanders and England. Issuing gold coins was yet another way to get money to finance such war. The masse d’or were issued as “false” Double-Florin: their weight was the same as two florins, but their fineness was 22 karats instead of 24 karats. Thus, they represent a clear attempt by Philip IV to obtain revenues through minting. The design of the coin is also remarkable as it had a big influence in the future gold coinage of France and other countries like Castilla, where kings were represented in a throne.
PHILIPPE IV, le Bel (1285-1314)
Masse d’or (1re émission, 10 janvier 1296). 7,01 g.
Le Roi assis de face, couronné, tenant le sceptre et un lis, dans un polylobe tréflé cantonné d’annelets.
R/ Croix feuillue et fleuronnée avec quadrilobe en cœur, cantonnée de quatre lis dans un quadrilobe aux quatre angles tréflés.
D. 208. C. 196. L. 212. Fr. 254.
Flan large et d’une grande fraîcheur de frappe. Superbe.
Un des fleurons de la numismatique médiévale française.