Identity theft?

How far should a novelist go in researching the names she gives her characters? Of course character names should be appropriate for the time and place the book is set.  Should a novelist investigate any further?

Recently, I was reading a review of a romance novel set in London in the 1830s. The hero was the Duke of Lennox. Lennox is a real Scottish dukedom that has been around, on and off, since the sixteenth century. The present line descends from an illegitimate son of Charles II. The holder of the title at the time the novel was set was the fifth duke, who had served with Wellington in the Peninsular campaign and subsequently entered politics. The character in the novel was not him.

Another time, I came across a Regency romance in which the hero was Philip Stanhope. There was a real Philip Stanhope. Several of them, in fact. Stanhope was the family name of the earls of Chesterfield and the earls Stanhope. Four earls of Chesterfield and three earls Stanhope were called Philip.

Philip, fourth Earl of Chesterfield (1694-1773) is best known for his letters to his son.

Philip, fourth Earl Stanhope (1781-1855) was a somewhat eccentric, well travelled man - characteristics he shared with his much more famous half-sister, Lady Hester Stanhope. But again, the character in the novel was not him.

The Stanhopes who entered politics did not rise to very high office, but they were well connected with those who did. Lady Hester's maternal grandfather was William Pitt the Elder, first Earl of Chatham. Her maternal uncle was William Pitt the Younger. Until his death she lived with him and acted as hostess for him, as he was unmarried.

The third Earl Stanhope's second wife, Louisa Grenville, was stepmother to Lady Hester and mother to the fourth earl. She was niece to one Prime Minister, George Grenville, and cousin to another, William Grenville.

Dukedoms and earldoms are unique; they can only be held by one person at a time. A writer cannot, therefore, say that her character just happens to have the same name as a real life aristocrat. None of this information is hard to find, especially when someone is already researching the period.

These people may not have been especially great or heroic or distinguished, but they lived their lives and had their achievements. Novelists have plenty of names to choose from. Why take one away from a real person?