JackGiantkiller said:
In Germany, perhaps. But in Western Europe a prince outranks a duke, and the eldest sons of dukes are [by courtesy, not law] marquesses.
An over-generalisation. In France and England the sons of the kings were simply princes, and that only comparatively late. Edward I was known as "Lord Edward" until his father died. Edward II was the first prince in the English peerage (created Prince of Wales at the age of two, about 1300).
Some were. For example the Dukes of Burgundy, with their independent foreign policy in the Hundred Years War. Or the Dukes of Aquitaine before the marriage of Elanor of Aquitaine (about 1137). The German dukes were practically sovereign after the steam went out of the Empire, but so were hundreds of landgraves, (counts), bishops, archbishops, and princes ruling domains barely the size of a decent farm. Legally the German dukes were a distinct cut below kings, and they used to scheme for the kingdoms of (for example) Moravia, Bohemia, Poland, Prussia and so forth that were outside the Empire and therefore not forbidden a sovereign title. This to my mind clearly shows that even wealthy and powerful dukes (such as the Duke of Saxony) felt at a disadvantage without a royal title, even of some tin-pot place like Moravia. The Germany duchies were all upgraded to kingdoms in 1806.
There were also counts with no feudal overlord, such as the Count of Toulouse, the Count of Barcelona, the Count of Savoy, and the Count of Provence. And at least one simple 'lord' with no feudal overlord (the Lord of the Isles until Scottish conquest).
And a subject of the Emperor, at least in theory.
