After the death of Emperor Leopold, Sinzendorf gained the favor of Emperor Joseph I, who made him in 1705 Court Chancellor (Obersthofkanzler). He was also the protector of the Imperial Academy of Arts. He was a central figure for four decades, especially in the foreign policy of the Habsburg Empire. In 1706 he negotiated in The Hague with
John Churchill, 1st Duke of Marlborough and the Netherlands' representatives. He was next to Eugene of Savoy in 1709 and negotiator in the negotiations to a preliminary peace that failed, because of the excessive demands from the side of Sinzendorf. In this way he succeeded in preventing a premature Austrian demand for peace. The Emperor rewarded Sinzendorf for his services by awarding him the fiefs of Hals and Schärding in Bavaria. Surprised by the death of the Emperor in The Hague, he went immediately to Frankfurt am Main to lobby for the election of Charles VI as Holy Roman Emperor. After the election, Charles VI confirmed Sinzendorf in his offices and while he accompanied Charles to his coronation in Frankfurt, Charles VI appointed him
Knight of the Golden Fleece. In negotiating the
Treaty of Utrecht, Sinzendorf teamed up with Prince Eugene and tried in vain to persuade the former allies to continue the war. Back in Vienna, he was appointed as Privy Conference Minister. He was since then not only responsible for the exterior, but also for domestic politics. Since 1721 he was also the director of the
Imperial Privileged Oriental Company (Kaiserliche privilegierte orientalische Kompagnie). At the Congress of Soissons to end the
Anglo-Spanish War (1727–29), he opened the negotiations. He came in contact with the French cardinal and statesman
André-Hercule de Fleury. His efforts were in vain and he returned to Vienna. In the negotiations with the Protestants in Hungary, he was present in 1734 as the only layman. He was an ardent supporter of the marriage of Maria Theresa and Francis Stephen of Lorraine. This he did also because he hoped it would bring him personal material benefits. After the
War of the Polish Succession, Sinzendorf led the peace negotiations for Austria, which led to the
Treaty of Vienna (1738). The defeats of the Imperial forces in the
Austro-Russian–Turkish War (1735–39) prompted him to urge the Emperor to an early peace. After the emperor's death, he supported
Maria Theresa in claiming her inheritance rights. Even in the early years of the
Austrian Succession War, he remained in the service of the Empress. == See also ==