It may well be a surprise to many of the visitors to the north of France to discover that the reason there is this huge citadel here in the town is because it used to be the frontier between France and the Spanish Netherlands.
Everything is bound up in family histories as to who inherited what - which is of course why the English fought Crécy and Azincourt.
In theory the Duke of Burgundy who was lord of Flanders and Artois owed allegiance to the King of France but in reality he was a rival king with a court that outclassed that of Paris. In Flanders and the Netherlands the phrase: to eat or live like a Burgundian, still means to live very well.
Needless to say there were numerous revolts and mini-wars throughout this period of history as one house attempted to dominate another.
In 1475 Louis XI of France burnt Doullens down for having sided with the then Duke of Burgundy: Charles the Bold.
On Charles's death in 1477 the Duchy of Burgundy came back into France whilst his northern territories became the possessions of his son in law: Maximilian. In turn, on his death, it passed into the hands of his grandson Charles Quint; Holy Roman Emperor and King of Spain. Thus Flanders and Artois as we know it today were under Spanish rule - despite supposedly being fiefs of France.
In 1521 Charles's forces attempted to take Doullens but were fought off by the inhabitants and a company of 50 archers. Work began to fortify the town and in 1523 the Spanish were greeted with artillery placed on a rampart built by General Antoine de Créquy (The ruins of whose own castle are open to visit near Hesdin).
A few years later Robert Mailly built the first citadel out of stone. It consisted of four bastions and would be greatly enlarged over the years. Following yet another invasion by the Spanish in 1599, Henri IV ordered Errard Bar le Duc to modernise the fortress. Stone was no longer capable of withstanding new artillery pieces and so brick was used.
Work continued right up until the time of Louis XIII (The Three Musketeers, Richelieu etc) but in 1639 Louis launched an attack on the Spanish taking back the town of Hesdin. He then set about retaking Arras which fell the following year.
Suddenly Doullens found itself well behind the frontier and of no real military purpose. Ironically the same fate befell the newer citadelle created by Vauban at Arras. Designed to prevent counter attacks by the Spanish it would never see battle and would become known as: The Pretty, Useless.
For the next few centuries the citadel at Doullens would be used as a prison for political prisoners including Louis XIII's own brother: Gaston d'Orléans, who spent much of his time plotting against Cardinal Richelieu.
During the Revolution the 84 year old Maréchal de Mailly left his château at Mailly-Maillet responding to a call for aid by Louis XVI. The old Marshal led the Swiss Guards in trying to defend the Tuilleries on the 10th August 1792 but, they were massacred, and he was arrested and held in Doullens until his execution at Arras on 25 March 1794.
The citadelle was converted into a hospital used firstly by the French and ultimately by the 3rd Canadian Stationary Hospital.
The fact that the citadel was being used as a hospital did not stop the German airforce bombing it on the night of 29/30th May 1918 during their Spring Offensive.
The operating theatre was destroyed by a direct hit killing those within and setting the building alight.
Two surgeons, three Nursing Sisters, ten officer patients and a number of personnel and patients were killed whilst a number of others were injured (again ! in the case of the patients).
A number of those killed including some of the nursing staff are buried in Plot III of the Bagneux Cemetery at Gézaincourt - which is about a five minute drive away from the citadel.
Following the war the buildings became used as a home for delinquent girls until the invading Nazis took over the structure as an internment camp for political prisoners. Towards the end of the war they considered setting up the Headquarters for the V1 and V2 missile bases on the site, but this came to nought.
And so the citadel slowly fell into disuse and nature took her hold again.
Fortunately local inhabitants rallied to the cause of this remarkable structure and it is now slowly undergoing renovations.
Limited visits are possible during the summer and those wishing to take the chance should contact the local tourist office at the Beffroi.
The site is immense: 54 hectares and whilst there is not perhaps a great deal to visit or see the citadel represents an important moment in French military architecture. Apart from its size visitors do get the chance to visit some of the tunnels which seem to stretch for kilometres. On the walls there are names and dates scratched from the First World War but also going back a number of centuries.