One of the first examples occurred when Count Gonçalo I Mendes of Portucale (in northwest Portugal and considered as that country's original nucleus) took, in 987, the personal title of Magnus Dux Portucalensium ("Grand Duke of the Portuguese") and rebelled against his feudal lord, King Bermudo II of León.
Another example was the line of self-proclaimed grand dukes (legally dukes) of Burgundy in the 15th century, when they ruled most of present-day north-eastern France as well as almost the entire Low Countries.