Traditionally, the Welf lands were equally divided among sons. In 1684, however, the family agreed to adopt the principle of primogeniture, allowing the entire inheritance to pass to the eldest son and thus preventing further division of the Duchy of Brunswick-Lüneburg into insignificant statelets. The seventeen-year-old Maximilian William voiced no objection. On his eighteenth birthday, his father signed a contract with the Republic of Venice, whereby he sent him to the Morean War as general of Brunswick-Lüneburg troops and nominal commander of 2400 men. Maximilian William, however, was to be under actual command of a more experienced officer, and that officer was to take orders from the future Doge of VeniceFrancesco Morosini. The war lasted until 1688. Maximilian William's elder brother, Frederick Augustus, the second son, was killed in battle in 1690. His death made Maximilian William the Duke's second son and prompted him to claim the right to inheritance he had been deprived of in favour of his eldest brother, George Louis. Maximilian William and his second-youngest brother, Christian Henry, announced that they would not recognize the adoption of primogeniture. Maximilian William proceeded to plot to set primogeniture aside, assisted primarily by the Master of the Hunt Joachim von Moltke. Anthony Ulrich, Duke of Brunswick-Wolfenbüttel, and the prime minister of Brandenburg Eberhard von Danckelmann were also implicated, and it is believed that Duchess Sophia was aware of the conspiracy but did not wish to estrange herself from her younger sons. His sister, Electress Sophia Charlotte of Brandenburg, informed their father of the plot by letter in 1691. Maximilian William and Moltke were imprisoned at the end of the year and charged with high treason. Moltke was executed, while Maximilian William was exiled the following year. He first sought protection from his paternal uncle, George William, and then went to Vienna to serve Emperor Leopold I.
Imperial service
Serving the Emperor, Maximilian William converted to Roman Catholicism in 1692 and rose to the rank of Field Marshal. He commanded the Hanoverian troops in the War of the Spanish Succession and was in command of the cavalry under Eugene of Savoy at the Battle of Blenheim. The Act of Settlement 1701 established that Maximilian William's mother Sophia, as a Protestant relative of Queen Anne, would succeed to the English throne, and that she would be followed by her Protestant descendants. Having converted to Roman Catholicism, Maximilian William forfeited his succession rights. Anne outlived Sophia by less than two months, both dying in 1714. Anne was thus succeeded by Maximilian William's brother George Louis, who had inherited Brunswick-Lüneburg on their father's death in 1698. Maximilian William and Ernest Augustus were George Louis's only living brothers at the time, but unlike the latter, Maximilian William received no peerage titles from the new King of Great Britain. Maximilian William was elected Prince-Bishop of Osnabrück in 1715, but the election was declared void because it was the turn of a Lutheran to hold the office; it was thus granted to Ernest Augustus. Maximilian William died in Vienna on 16 July 1726.
