Sons of a Duke
The eldest (or only) son of a duke will use one of his father's lesser peerage titles. For example, the son and heir apparent of the Duke of Rutland is known as the Marquess of Granby and the appropriate forms of address for a Marquess by courtesy therefore apply to him and his family.
If the duke is of the peerage of Scotland please refer to Scottish Title of Master
Younger Sons of a Duke
The younger sons of a duke have the courtesy title of 'Lord' before their forename and surname.
Prefixes such as His Excellency, Major General, The Rt Rev, The Rt Hon etc. precede his courtesy title.
How to address the Younger Son of a Duke
The recommended (social) style of address is as follows:
| Beginning of letter | Dear Lord Edward |
| End of letter | Yours sincerely |
| Envelope | Lord Edward Fitzgerald |
| Verbal communication | Lord Edward |
| Invitation* | Lord Edward Fitzgerald |
| Description in conversation | Lord Edward |
| List of Directors or Patrons | Lord Edward Fitzgerald |
| Place card | Lord Edward Fitzgerald |
| Legal document | Edward Fitzgerald commonly called Lord Edward Fitzgerald ? |
*Note that, traditionally, invitations to a married couple, when sent to their home address, are addressed to the wife alone, with both names being inscribed on the invitation card. It has become increasingly acceptable, however, to address the envelope with both names.
Wife of the Younger Son of a Duke
The wife of the younger son of a duke has the courtesy title of 'Lady' followed by her husband's forename and surname (unless herself the daughter of a duke or marquess *)
How to address the Wife of a Younger Son of a Duke
The wife of the younger son of a duke has the courtesy title of 'Lady' followed by her husband's forename and surname (unless herself the daughter of a duke or marquess *).
How to address the Wife of a Younger Son of a Duke
The recommended (social) style of address is as follows:
| Beginning of letter | Dear Lady Edward |
| End of letter | Yours sincerely |
| Envelope | Lady Edward Fitzgerald |
| Verbal address | Lady Edward |
| Invitation | Lady Edward Fitzgerald |
| Description in conversation | Lady Edward |
| List of Directors or Patrons | Lady Edward Fitzgerald |
| Place card | Lady Edward Fitzgerald |
| Legal document | Helen Fitzgerald commonly called Lady Edward Fitzgerald |
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*If she is the daughter of a duke, marquess or earl, she may continue to use her own title instead of that of her husband. This style should only be used if it known to be the preferred form of address. Widow of the Younger Son of a Duke Her style in widowhood does not change, except on remarriage, when she adopts the style from her new husband. |
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