Metternich's shadow
Hardenberg now had a position in that close corporation of sovereigns and statesmen by whom Europe was governed. He accompanied the allied sovereigns to England and at the Congress of Vienna (1814-1815) was the chief representative of Prussia. However, the zenith of his influence, if not of his fame, had passed. In diplomacy, he was no match for Klemens von Metternich, whose influence soon overshadowed his own in the councils of Europe, Germany and ultimately even Prussia itself.
At Vienna, in spite of the powerful backing of Alexander I of Russia, he failed to secure the annexation of the whole of Saxony to Prussia. In the Second Treaty of Paris, after the Battle of Waterloo, he failed to carry through his views as to the further dismemberment of France and had weakly allowed Metternich to forestall him in making terms with the states of the Confederation of the Rhine, which secured to Austria the preponderance in the German federal diet. On the eve of the conference of Carlsbad (1819) he signed a convention with Metternich in which, according the historian Heinrich von Treitschke, 'like a penitent sinner, without any formal quid pro quo, the monarchy of Frederick the Great yielded to a foreign power a voice in her internal affairs."
At the congresses of Aix-la-Chapelle (Aachen), Troppau, Laibach and Verona, the voice of Hardenberg was but an echo of that of Metternich. The cause lay partly in the difficult circumstances of the loosely-knit Prussian monarchy but partly in Hardenberg's character had never been well balanced but had deteriorated with age. He continued amiable, charming and enlightened as ever, but the excesses that had been pardonable in a young diplomat were a scandal in an elderly chancellor and could not but weaken his influence with so pious a Landesvater as Frederick William III.
To overcome the king's terror of liberal experiments would have needed all the powers of an adviser at once wise and in character wholly trustworthy. Hardenberg was wise enough and saw the necessity for constitutional reform, but he clung with almost senile tenacity to the sweets of office, and when the tide turned against liberalism, he allowed himself to drift with it. In the privacy of royal commissions, he continued to elaborate schemes for constitutions that never saw the light, but Germany, disillusioned, regarded him as an adherent of Metternich, an accomplice in the policy of the Carlsbad Decrees and the Troppau Protocol.
In 1814, King Frederick William III vested Hardenberg with the locality of Quilitz, together with the princely title, as a gratification for his merits as Prussian state chancellor. When he received the manor, he renamed the place right away into Neuhardenberg (New Hardenberg). From 1820 on, he had the mansion and the church rebuilt in neoclassical style, according to plans designed by Karl Friedrich Schinkel, while the gardens were redesigned by his son-in-law, Prince Hermann von Pückler-Muskau, and Peter-Joseph Lenné.
Hardenberg died at Genoa soon after the closing of the Congress of Verona. Hardenberg's Memoirs, 1801-07 were suppressed for 50 years after which they were edited with a biography by Leopold von Ranke and published as Denkwürdigkeiten des Fürsten von Hardenberg (5 vols., Leipzig, 1877).
