A duke's eldest
The younger sons of a duke or marquess have the courtesy style of "Lord" before their forename and surname. The younger sons of an earl, and all sons of a viscount or baron and daughters of a viscount or baron have the courtesy style of "The Hon" before their forename and surname.
The younger sons of a duke or marquess have, by courtesy, the title of lord prefixed to their forename and surname—e.g., Lord John Russell (as a younger son of the Duke of Bedford).
The title used does not have to be exactly equivalent to the actual peerage. For example, the eldest son of The Duke of Wellington is usually styled "Marquess of Douro", although the actual peerage possessed by his father is Marquess Douro (not of Douro).
The 2nd and subsequent children of a Duke would get the courtesy title of “Lord/Lady <name>”. Since the title of Lord/Lady doesn't have the ability to have their children have any courtesy titles, the children of these 2nd children would just be known as “Mr./Miss”.
⚡ Quick summary. A prince is typically the son or grandson of a monarch. The title duke is typically bestowed to a male member of the monarchy, often identifying him as a ruler of a territory known as a duchy. In some cases, a prince can also hold the title of duke, but prince is usually the higher-ranking position.
Nope. In short, princes are born and dukes are made. Take Prince Edward for instance. Queen Elizabeth's youngest son was not given a duke title when he got married.
The holders of the dukedoms are royal, not the titles themselves. They are titles created and bestowed on legitimate sons and male-line grandsons of the British monarch, usually upon reaching their majority or marriage.
Normally, the dukedom would descend to the duke's eldest son. But if he has already died, the dukedom would pass to the eldest son's eldest son.
After the duke's son died, the patent for the dukedom was amended by parliament to allow his daughters and their sons to inherit the dukedom successively.
The highest grade is duke/duchess, followed by marquess/marchioness, earl/countess, viscount/viscountess and baron/baroness. Dukes and duchesses are addressed with their actual title, but all other ranks of the peerage have the appellation Lord or Lady. Non hereditary life peers are also addressed as Lord or Lady.
Duke is a male title either of a monarch ruling over a duchy, or of a member of royalty, or nobility. As rulers, dukes are ranked below emperors, kings, grand princes, grand dukes, and sovereign princes. As royalty or nobility, they are ranked below princes and grand dukes.
The highest and most important nobility rank in all four peerages of the British Isles is Duke, the name of which comes from the Latin dux, meaning leader. The female equivalent is Duchess, a title bestowed on a woman who holds the title in her own right, as well as one who is the wife of a Duke.
The critical fact is that the duke is sovereign. A sovereign ruler use any title including Duke, Grand Duke, ArchDuke or "poobah and bottle washer"; the heir apparent to a sovereign rule is a "Prince" unless local tradition or autocratic decree mandates a different title.
The children of a viscount are known as The Honourable [Forename] [Surname], with the exception of a Scottish viscount, whose eldest child may be styled as "The Honourable Master of [X]".
As listed, the hereditary titles are: Duke, Marquess, Earl, Viscount, and Baron. Commoner titles include the Lord, which isn't really a hereditary title within the United Kingdom.
How to become a duke. Whereas (generally) the title of “Prince” requires royal blood, the title of “Duke” does not. While dukedoms can be inherited directly from a parent, they can also be bestowed by the reigning king or queen.
The Duke of Edinburgh dukedom is not hereditary, meaning it will not automatically be passed onto James on his father's death. The youngest of Queen Elizabeth II's eight grandchildren, the Earl of Wessex, 15, was understood to be a particular favourite of Her Majesty's.
“If a duke only has a daughter, will she become a duchess after his death?” Not in the UK; all the extant British dukedoms pass exclusively in the male line according to their Letters Patent. That's why when Prince Andrew dies, York will go extinct and revert to the Crown rather than passing to Princess Beatrice.
A duke's eldest son and heir is often a marquess, though he can also be an earl, viscount, or baron. The title given to the heir is a lesser title of the peer, usually the next highest peerage he holds.
If the daughter of a duke marries a peer, she takes his title. If she marries the eldest son of a peer, she takes his title, but in the case of the heir of an earl or lesser peer, she may choose to keep her own title until her husband inherits.
In status, a grand duke traditionally ranks in order of precedence below an emperor, as an approximate equal of king or archduke and above a sovereign prince or sovereign duke.