Adam Albert von Neipperg

In 1809, after the Austrian campaign, he was appointed ambassador to Sweden and encouraged Bernadotte to enter in the coalition which was formed in 1813. In reward for this service, he was decorated by the Swedish king. Neipperg rejoined the Austrian army and fought at Leipzig where he distinguished himself sufficiently to be appointed as lieutenant field marshal.

In 1814, Klemens von Metternich sent him to negotiate with the King of Naples, Joachim Murat, who signed a secret peace treaty with Austria in order to keep his throne. Metternich's other intrigue was to try to distance Prince Eugene (stepson of Napoleon and son-in-law of King Maximilian I Joseph of Bavaria) from the French. When Napoleon returned from exile, Murat once again allied with his brother-in-law the Emperor, triggering the Neapolitan War.

Neipperg commanded a corps in the Austrian army (called the Army of Naples) under Field Marshal Frederick Bianchi. Murat dispatched General Carrascosa with a division of Neapolitan troops to prevent Neipperg's corps linking up with Bianchi and the Austrian main body. Neipperg defeated Carrascosa at Scapezzano on 1 May 1815. The main Neapolitan force under Murat's command attacked Bianchi's smaller force, which was in a strong defensive position, at Tolentino on 2 May 1815. The attack was renewed on 3 May and the Neapolitan force was gaining an advantage over the Austrians, when Murat received news of Carrascosa's defeat. With the threat of Neipperg's large force approaching his flank, Murat had to order the Neapolitan army to withdraw, turning Tolentino from a potential Napoleonic victory into a defeat.

In 1815, Neipperg participated in the short occupation of France. In July 1815, as the Austrian army crossed the Rhone, he took command of the troops in the French departments of Gard, Ardèche and Hérault. He was under the supervision of Bianchi, commanding the Austrian army in the south of France. He lived in Nîmes and left the city with the rest of the troops on 14 September 1815.

In August 1814, he was instructed to escort Napoleon's wife, the Empress Marie-Louise, to Aix-les-Bains to take the waters. However, the true purpose of his mission was to prevent the Empress from joining Napoleon in exile in Elba. Neipperg, who had understood this perfectly, was rumored to have told his mistress in Milan: "Inside of six months I shall be her lover, and soon her husband".[3] The quote is most likely apocryphal, and at any rate, he did not need that long, as the Empress soon became his lover and talk of Elba never arose again.[4]

Four months after the death of Napoleon I in 1821, he married Marie-Louise in a morganatic marriage. She had become sovereign Duchess of Parma, Piacenza and Guastalla, styled Maria-Luigia di Parma, in the final act of the Congress of Vienna on 9 June 1815. From this union, four children were born, the first two before the marriage, whilst Marie-Louise was still legally married to Napoleon:

1. Countess Albertine di Montenuovo (Italian translation of Neipperg) (1817–1867), who married Luigi Sanvitale, Count di Fontanellato, in 1833.
2. William Albert, Count, then 1st Prince von Montenuovo (1819–1895), who married Countess Juliana Batthyány von Németújvár, in 1850.[5]
3. Countess Mathilde di Montenuovo (b. 1822), who died young.[6]

Neipperg died in Parma on 22 February 1829 of a heart condition. His descendants with the Duchess Maria-Luigia, the Princes von Montenuovo, intermarried with the Austro-Hungarian nobility and served as courtiers and diplomats at the Imperial Hofburg in Vienna, dying out in the male line in 1951.