Napoleon III responded with a show of force, sending the ship of the line Charlemagne to the Black Sea. This action was a violation of the London Straits Convention.:104:19 Thus, France's show of force presented a real threat, and when combined with aggressive diplomacy and money, induced the Ottoman Sultan Abdülmecid I to accept a new treaty, confirming France and the Roman Catholic Church as the supreme Christian authority with control over the Roman Catholic holy places and possession of the keys to the Church of the Nativity, previously held by the Greek Orthodox Church.:20