Sir | Sir Walter Scott | 3rd Rock from the Sun | baronet | Baronet | Nicholas II of Russia | Saint Nicholas | Nicholas I of Russia | Sir Arthur Conan Doyle | South Carolina's 3rd congressional district | Nicholas II | Robert Gascoyne-Cecil, 3rd Marquess of Salisbury | Nicholas I | Sir Robert Peel | Nicholas Nickleby | Michigan's 3rd congressional district | Thomas Fairfax, 3rd Lord Fairfax of Cameron | Nicholas Ray | 3rd United States Congress | Nicholas Roerich | Nicholas Briggs | Fernando Álvarez de Toledo, 3rd Duke of Alba | 3rd arrondissement of Marseille | St. Nicholas | Sir Arthur Harris, 1st Baronet | Sir Raylton Dixon | Sir Harold Hillier Gardens | Sir Fitzroy Maclean, 1st Baronet | Nicholas of Cusa | Nicholas Longworth |
His father, William Harcourt Isham Mackworth (1806—1872), a younger son of Sir Digby Mackworth, the 3rd Baronet, took the additional surname Dolben after he married Frances, the heiress of Sir John English Dolben, the 4th Baronet.
One of the Colthurst baronets his father was the Sir John Conway Colthurst was the first baron and also an Irish Parliamentarian, his older brother also called Sir John Conway Colthurst was the 2nd Baron but died in a duel in 1787.