Duke of Amalfi

Medieval Amalfi was ruled, in the tenth and eleventh centuries, by a series of dukes (Latin: duces), sometimes called dogi (singular: doge), corresponding with the republic of Venice, a maritime rival throughout the Middle Ages.

The title of Duke of Amalfi was reestablished as a Spanish dukedom in 1642 by King Philip IV of Spain for Ottavio Piccolomini, an Imperial field marshal.

It reigned uninterrupted for the next 115 years, except during the period 1039–1052, when the duke of Salerno conquered the duchy.

A certain Manso ruled Amalfi—minting his own currency—under the title of vicedux (Vice-duke) sometime between 1077 and 1096, most probably during the reign of Robert's son Roger Borsa.

That changed in 2006, since when the eldest child (regardless of gender) can automatically succeed to noble family titles.