The war occurred during the Hundred Days between Napoleon's return from exile and before he left Paris to be decisively defeated at the Battle of Waterloo.

As defeat in the War of the Sixth Coalition loomed, Murat increasingly moved away from Napoleon, eventually signing a treaty with Austria in January 1814 and joining the Allied side.

At the start of the war, Murat reportedly had 82,000 men in his army, including 7,000 cavalry and 90 cannon, although this figure was grossly exaggerated to try to encourage Italians to join his cause.

Leaving behind a reserve Army of the Interior in case of an invasion from Sicily, he sent his two elite Guard Divisions through the Papal States, forcing the Pope to flee to Genoa.

Under the terms settled by the Congress of Vienna, direct Austrian rule was restored in the Duchy of Milan 19 years after Napoleon's invasion.

However, no such general insurrection occurred, as any unrest was quickly quashed by the Austrian authorities, and Murat found few Italians outside Naples who were willing to take up arms and join his cause.

Meanwhile, on the same day that Murat gave the Rimini Proclamation, the Austrian advance guard, under the command of General Bianchi, was beaten back at an engagement near Cesena.

Following the battle, the division under the command of General Carrascosa immediately occupied Modena, Carpi, and Reggio Emilia, while Murat moved against Ferrara.

Murat had received little reinforcement from the Italian populace up to this point, but he hoped he would find more support north of the Po River, which was under direct Austrian rule.

The region had once been part of the Kingdom of Italy, a French client republic, and it had been reported that about 40,000 men, mostly veterans of Napoleon's campaigns, were ready to join Murat once he arrived in Milan.

The Grand Duke fled to Pisa, while the Austrian garrison in Florence, under the command of General Nugent, was forced to retreat to Pistoia, with the Neapolitan army in pursuit.

Murat's attempts to cross the River Po proved unsuccessful, and after two days of heavy fighting, the Neapolitans fell back after suffering over 2,000 casualties.

By 15 April, the Austrians had retaken Florence, and when the news reached Murat, he ordered a general retreat of his main force back to their original headquarters in Ancona.

With the road to Florence now clear and the Italian peninsula opening up in front of him, Frimont ordered two corps south to deal with Murat once and for all.

With the war turning in Austria's favour, Frimont was ordered back to Lombardy to oversee the army that was now amassing in preparation for an invasion of France.

Murat, who placed too much faith in his Guard Divisions, believing they would be able to halt the advance of Bianchi and Nugent, retreated slowly, even turning to check the pursuit at the Ronco and Savio rivers.

Murat hurried his retreat, and by late April, his main force had arrived safely in Ancona, where he was reunited with his two Guard Divisions.

Much like Napoleon's tactics before Waterloo, Murat sent a division under Carrascosa north to stall Neipperg while his main force headed west to face Bianchi.

Murat was forced to flee to Corsica and later Cannes disguised as a sailor on a Danish ship after a British fleet blockaded Naples and destroyed all the Neapolitan gunboats in the harbour.

Although Joachim Murat failed to save his crown or start a popular nationalist movement with the Rimini Proclamation, he indirecly and unintentionally ignited a desire for Italian unification.

The intervention of Austria only heightened the fact that the Habsburgs were the single most powerful opponent to unification, which would eventually lead to three wars of independence against the Spanish Bourbons Austrians.