Generally speaking, it would be a "Joint Command" that has line authority to oversee the management of multiple incidents being handled by separate Incident Command organizations, since in this case different agencies are "joined" together.
The guilds , banks , and money system which began in medieval europe : Were the start of modern market economies and trade unions
Before the bank and money system, the merchants have to pay their goods with another goods in a barter system. This often create some dispute because of 'unfairness' . The money system allowed one specific currency as a standard to exchange goods and services and eliminate this unfairness
