How did the demand for goods affect both the power of the italian states and the catholic church?

Heck it made them more powerful over the citizens. The Venetian trade ships carried goods during the crusade and from then on Italy was kind of like a middle trade route with a booming rich economy. The church taught that the pope was highest political figure. Also the demand for goods let them impose huge taxes on the goods leaving and entering their shores. 

The dangers of an inadequate monetary supply.