Conversation so far:
What sort of achievements did the Archduke Charles, Duke of Teschen have?
Despite being epileptic, Archduke Charles, Duke of Teschen achieved respect as a commander and as a reformer of the Austrian army. He was considered one of Napoleon's more formidable opponents.

Question: How long did he reign?
Self-contained rewrite: How long did the Archduke Charles, Duke of Teschen reign?