Question: The "black spider" memos are letters and memos, to British government ministers and politicians over the years, written by Charles, Prince of Wales, the eldest child and heir apparent of who?
Sentence (from "Charles, Prince of Wales"): Known alternatively in Cornwall as Duke of Cornwall and in Scotland as Duke of Rothesay, he is the longest-serving heir apparent in British history, having held the position since 1952.
Relevant evidence: No