Greece of this era was based on affiliations with the three Great Powers, and Otto's ability to maintain the support of the powers was key to his remaining in power. To remain strong, Otto had to play the interests of each of the Great Powers’ Greek adherents against the others, while not aggravating the Great Powers. When Greece was blockaded by the (British) Royal Navy in 1850 and again in 1853, to stop Greece from attacking the Ottoman Empire during the Crimean War, Otto's standing amongst Greeks suffered. As a result, there was an assassination attempt on the Queen and finally, in 1862, Otto was deposed while in the countryside. In 1863 the Greek National Assembly elected Prince William of Denmark, aged only 17, King of the Hellenes under the regal name of George I. The law of succession to the throne of Greece was defined by a supplementary article to the convention of 7 May 1832 awarding the Greek Throne to Otto I. It instituted a semi-salic order with an important rule preventing the union of the crown on the same head with any other crown, especially that of Bavaria. The 1844 constitution further made provision for his succession by his two younger brothers (Luitpold and Prince Adalbert of Bavaria) and their descendants. Under the terms of the succession law, a Wittelsbach claim to the throne would have passed on Otto's death in 1867 to his younger brother Luitpold, who was regent of Bavaria from 1886 to 1912; and theoritically after him to Ludwig who became king Ludwig III of Bavaria in 1913. At this point, tracing the claim becomes problematic as the same branch of the Wittelsbach became heir to both thrones, and a subsequent monarch or pretender should have issued a renunciation to one of the two thrones, which none did. In the end, neither Luitpold nor his son Ludwig actively pursued a claim to the Greek throne inherited from Otto, and the throne of Bavaria itself disappeared in 1918, leaving the future of the claim to be decided by a further arrangement that never occurred. However, Ludwig's marriage to Maria Theresia of Austria-Este in 1868 came with a caveat. Maria Theresa's uncle, Duke Francis V of Modena, was a staunch Roman Catholic. He required that as part of the marriage agreement Ludwig renounce his rights to the throne of Greece, and so ensure that his children