] ] I had always been of the understanding that the title "Viscount" was held by the heir of a landowning Lord who, once the Lord was deceased, then attained the title of Lord ____, and subsequently the new Lord's heir then became the Viscount.

] Like so many things English, this is a trick they play to confuse outsiders. Here's a link to a basic introduction to the system of British titles.

Thank you, kindly. I shall be visiting this link forthwith.

] Your particular situation is this. As a family rose in rank through the aristocracy, the bearer of the title kept his the junior titles that he or his ancestors had picked up. For example, the Marquess of Anglesey was also the Earl of Uxbridge and Baron Paget.

] It was customary for the oldest son of a peer to use one of the junior titles as his courtesy title, as long as it was different from his father's.

Your explanation makes it very clear, and if I follow you correctly, the present day Prince of Wales and Duke of York are family titles which Queen Elizabeth II would hold thus they are hers to grant. Following this line of thought then, would Prince Charles, upon assumption of the throne, have the right to revoke his brother's use of the title Duke of York, since he has assumed the monarch's position?