The answer is: It wasn't even about the taxes to pay off debt anymore, it was to show that he was in control.
Merchant families that ruled Italian city-states established: B. their own armies.
In the Renaissance epoch, Italy was formed by many city-states with powerful people as the rulers. They were in conflict with each other quite often. That is why these cities had their own armies to protect their merchant, their political interests and their cultural influence in the region.
They fought in World War ll against the Allies. I don’t know anything else other than the fact they were in WW2.