In the Middle Ages, and even up to the early twentieth century, most of Europe's executioners were related: the Sansons and Deiblers in France, the Pierrepoints in England, etc. The reason for this was that, it generally not being socially acceptable to, well, kill people, executioners and their children could, generally, only marry other executioners or their children.
The parallels with massively inbred, Hapsburg-style dynasties are obvious- imagine a rather clever but politically inept satirist noting this, and being sentenced by the latter to a meeting with the former; even worse, imagine a dynasty of deranged and deformed executioners- think Texas Chaisaw Massacre with government funding.
The court wizards of Angolterre have been working for several generations to protect the dynasty. They see to it that the new monarch's names acronymically refer to a rune of protection. Once completed, the rune will make the dynasty almost invulnerable in battle, wise in counsel, etc. Unfortunately the next name, the only one that starts with the right letter, happens to have belonged to the worst monarch in living memory. Not much chance of getting the current ruler to name his child that, or for the people to put up with it if he did! What's a court wizard to do? The magic requires that the plot be kept secret of course...