How did the rights and duties of counts in the administration of the empire differ from the rights and duties of dukes?

The Count is the oldest of the titles of nobility, as it dates back to the Roman Empire. Counts’ names are often associated with the city where they rule. The count has few military powers, rights and responsibilities.

The Duke was originally primarily a purely military title associated with the command of armies in one of the border marches of the Roman Empire. Then there is a change in meaning when the owners of large territorial groups receive this title and, therefore, powers in a number of districts. It was then that very important duchies were formed.