The Papacy in the Late Middle Ages
Papal Government
Conclusion
When you read about the "centralization" of papal government in these centuries, then, you should see an interlocking network of effects. The popes needed money and sought to exploit existing resources and find new ones. This required new officials and new offices. As the papacy acquired more visible and effective authority, more and more people found reason to send their petitions (they were also trying to out-maneuver increasing royal authority). This again caused papal government to grow. Every new office meant new expenses, though. All these tendencies were intensified as the popes had to create a whole new capital at Avignon even as they tried to regain control of their old one in Rome.
In short, the need for money skyrocketed, and the size of government skyrocketed. In this, developments at the papacy were on a parallel with developments in the secular kingdoms.