How was the period when
Rome ruled most of Europe
different from the Middle Ages?

Politics during the period of Rome is governed by an emperor having their city as a state. It includes the relationship between the landowners having vast lands cultivated by peasants and slaves with the protection of nobles in return for having partial lands for payment. Its economic system is both feudal and slavery. 

The middle ages have the role of a monarchy government and the power of a clergy in the decision making. It has a larger scope of land compared to the Romans. It has a feudal economic system and at the stage of a diminishing slavery system.

Explanation:

when a country suffers, for example, a drought period, the market product is affected for a low offer, in this case, potatoes; the government has to tax to the households, which have to give more money for the potatoes which they consume, that situation make them consume substitute goods even through loans, it could increase the financial market movement and the inflationary phenomena, the business has to increase salaries in order to the employees could buy a more expensive food (potatoes) and in order to inflation tha business had to buy expensive supplies in the factor market, while the rest of the world have to gain more money to consume the same amount of potatoes.