Charles, the younger brother of King Louis IX of France, had just acquired the crown of Naples, and Philip traveled with him in his service to southern Italy.
Philip lived a good life as count of Chieti and Teano, until news reached him of the great Flemish victory in the Battle of the Golden Spurs.
The existing Bishoprics of Arras, Cambrai and Tournai were still under the influence of France, and excommunicated many Flemish nobles to break their resistance.
On 18 August 1304, King Philip IV of France launched a new attack against Flanders, one week after the Flemish defeat in the Battle of Zierikzee, in which Guy of Namur was taken prisoner and John III, Lord of Renesse killed.
Philip of Chieti took command over a strong Flemish army to stop the French invasion and fought the inconclusive Battle of Mons-en-Pévèle.