Final answer:
Philip IV helped unite France by asserting control over the Catholic Church and relocating the papacy to Avignon, France.
Step-by-step explanation:
Philip IV, also known as Philip the Fair, used his power and influence to help unite France in several ways. One of the main actions he took was to exert control over the Catholic Church in France. He suppressed the power of the church and even went as far as to remove Pope Boniface from Rome, ultimately leading to the relocation of the papacy to Avignon, France. This gave the French monarchy greater authority and strengthened national unity.