On 10 March 1821, during the Piedmont insurrection, the blue, red and black tricolour of the Carbonari was raised on the Cittadella's bastions by Colonel Ansaldi.

In order to meet the needs of defense of the new state of Savoy, it was decided to build a massive fortress designed to function as a barrier of military transits traveling along the "Road of Flanders", the ancient Spanish military road that connected the harbors of Genova, Savona and Finale Ligure with the Netherlands.

The Citadel was built entirely at the expense of the ancient quarter of Borgoglio (or Bergoglio) provoking strong urban revolution.

It was completed in its main components in the 1740s while inside the fortified hexagon the buildings of the civilians were gradually demolished to make way for new military quarters and the inhabitants were forced to relocate, replaced by a garrison ever more numerous.

The Citadel is a perfect example of modern fortress composed of six bastioned fronts supplied with cavalieri crossed by tunnels and casemates.

The entrance is by a long stone bridge that leads to a large area surrounded by multi-storey buildings arranged along the axis of the ancient quarter, all protected by resistant embankments constructed between 1749 and 1831.

The Citadel was tested by fire the first time between 1745 and 1746 when it resisted the French-Spanish army for seven months, during the War of the Austrian Succession.

At the end of the First Italian Campaign, the Citadel was in the hands of the French: in July 1799 it was under siege by the Austro-Russian Army led by Aleksandr Vasilyevich Suvorov.

On 10 March 1821, the Cittadella's garrison mutinied, marking the beginning of the Piedmont insurrection, and Colonel Ansaldi raised the blue, red and black tricolour of the Carbonari on the bastions.

On 18 June 2010, a permanent exhibition of about 1500 uniforms, weapons and memorabilia of the Royal Italian Army was established within the fort.

In 2014, the Cittadella was listed as one of "The 7 Most Endangered" sites by Europa Nostra, mainly due to the spread of weeds which threatens the fortification.