There were pawn brokers and money changers. Some people were money lenders who charged interest for money borrowed. A double entry system of bookkeeping was introduced by a 15th century Franciscan monk named Fra Luca Pacioli. He is known as the Father of Bookkeeping. The idea of of diplomacy was new to the Renaissance.
Ambassadors follow the tradition of diplomacy.
This means that they must present credentials of who they are, who they represent and their mission to the country where they are beginning their tour of duty. In the Renaissance, developments in weaponry were very important because the weapons made battle easier. You could hurt your enemy without have to go close to them. The Europeans adopted the use of gunpowder from the Far East. Cannons were useful because you could hit the enemy from a long distance.