Courtesy title

In the hereditary Napoleonic and Restoration peerage, declension was a legal right of younger sons, the derivative title being heritable by male primogeniture; King Joseph Napoleon conferred the title "Prince" on his grandchildren in the male and female line.

In order to use the title of count, one had to own a seigneurie elevated to county and to comply with the remainder of the grant.

It was achieved in one of three ways: if the head of family held two dukedoms, his heir could use the junior one; the head of family could resign his French peerage to his heir, who assumed a new title of duke while the father retained his ducal title; the king could confer a brevet de duc, that is formally accord the non-hereditary style and precedence of a duke to the heir of a ducal title.

The younger sons of a noble titleholder used one of the family's lesser titles, but rarely one of duke or prince.

Even in untitled families of the nobility, every son used a different territorial designation, the so-called nom de terre.