 Henry, stuck in the Hohenstaufen conflict with the House of Welf until 1194, had to enforce the inheritance claims by his wife against her nephew Count Tancred of Lecce.Henry's attempt to conquer the Kingdom of Sicily failed at the siege of Naples in 1191 due to an epidemic, and following his retreat Empress Constance was captured.Based on an enormous ransom for the release and submission of King Richard I of England, he conquered Sicily in 1194; however, the intended unification with the Holy Roman Empire ultimately failed due to the opposition of the Papacy.