The land that is now modern day Italy would be a natural crossroads between Western Europe and the holy land.
As soon as The Pope called for a crusade, the ruler’s of the great merchant state’s Venice, Genoa and Pisa began to plot ways to help the Crusaders and benefit themselves.
Providing by ship, both money and relief forces. At a price of-course.
These 3 merchant states were constantly forming alliances with and against each other. Which could make dealing with them difficult but was often preferable to the land route.
Genoa. Pics related.