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The Crypt of Notre Dame Cathedral, Boulogne-sur-Mer


It isn’t often that I’m completely and utterly astonished but on a trip to Boulogne-sur-Mer on the Opal Coast recently – that’s exactly what happened. There is a church in the town that the Kings of France held in such high esteem that they made a pilgrimage there believing that if they didn’t, they would suffer a fate worse than death…

I’ve been to Boulogne-sur-Mer often and think it’s a little gem. Bustling, dynamic and the historic walled old town is quite beautiful, a real throw back in time with its chateau, ramparts, cobbled streets and quirky shops. Charles Dickens loved this town and lived in nearby Hardelot from 1860-1864, shopping often with his wife and family on the cobbled streets of busy Boulogne-sur-Mer.

That wasn’t what did it though.

boulogne-notre-dame-church-miraclesYou may have been to the magnificent Basilica of Notre Dame with its huge dome, frescoes and fragment of an ancient statue that is said to perform miracles. Judging from the number of thank you plaques on the wall – it may well be so. But what you may not have done is visit the crypt of that huge church and if you have you may not recognise it today. After several years of hard work and restoration the crypt has been re-opened to the public in May 2015 and it is stunning.

History of the Basilica Notre Dame of Boulogne-Sur-Mer

The medieval church in the town was held in very high esteem since legend had it that a statue of the Virgin Mary was bought ashore in 636 AD at Boulogne in a small boat, guided by a ministry of Angels. It attracted pilgrims from all over Europe. In fact Boulogne-Billaincourt, the Paris district takes its name from Boulogne-sur-Mer in honour of the fame of the church.

In 1479, Louis XI appointed the Earldom of Boulogne to the Virgin Mary, declaring her Countess of Boulogne. I have no idea how that worked by the way, I can’t find any documents about the result of her performance. He also gave to the church a heart of pure gold and decreed that all future kings must do so or suffer terrible misfortune. One of only two Kings who didn’t obey was Louis XVI who lost his head in the French Revolution during which, the medieval cathedral of Notre Dame was destroyed and left to rot.

When Father Benoît-Agathon Haffreingue (1785-1871) became head of a minor seminary located next to the ruins of the medieval cathedral he decided to rebuild it. In 1815, despite the fact he had never trained as an architect, with enormous passion and vision, he designed the plans for the Basilica and managed the construction site.


As the new church was to be constructed with the materials of the old building as much as possible,  the builders were instructed to dig out the crypt which had been filled with the rubble of the old church. They discovered an enormous crypt, complete with Roman columns – which is amazing enough in itself.

The longest Crypt in France

After the rubbish was cleared, the workmen made another incredible discovery – the longest crypt in France, it is over 100m long. There are dozens of little rooms leading off, some of them go back to Roman times when Boulogne-sur-Mer was a strategic location and the Roman conquerors built a port from which Julius Caesar planned an invasion against England (54-54 BC).


It’s not just the size though that is astonishing. It isn’t known who the artist is (or maybe there was more than one), but someone in the mid 1800’s spent perhaps a lifetime in the crypt creating frescoes and drawings on the walls and ceilings. Images of Saints, key figures from the Bible, Latin inscriptions, mythical creatures… hundreds of them – life size pictures created by an enormously talented artist. Father  Haffreingue also got involved in decorating the crypt, in one of the Roman tunnels he created a faux hill of Lazarus, complete with a tomb, steps and crosses, designed to be viewed from below in candle light; clearly a man with a theatrical spirit.

Chapel of General San Martin of Argentina

Boulogne-sur-Mer was the last home of Argentinian General José de San Martin, liberator of his country in 1816, Chile (1818) and Peru (1821). He died at Boulogne in 1850 and his body was laid in the crypt for 11 years until being repatriated to his homeland.

The Crypt of Boulogne-sur-Mer today

The rebuilding of the Basilica of Notre Dame was an incredible success for the unqualified architect Father  Haffreingue; a magnificent dome became an instant landmark, seen from miles around. In 1853 he was awarded the Cross of the Legion of Honour by Napoleon III. His grave can be seen in the crypt.

The visionary team who have restored the crypt have spent years making the passages safe without causing damage to the walls and ceilings, preserving the images and colours that the unknown artist produced.

Softly lit, accessible to all, the crypt is home to a fascinating collection of religious art including a priceless enamel relic which claims to contain the blood of Christ, bought back from Jerusalem in 1100 by Godfrey de Bouillon (1061-1100), son of the Count Eustace of Boulogne, Duke of Lower Lorraine and King of Jerusalem (1099). Whether you believe in it or not, this relic is of incredible historical importance.


There are hearts of gold, golden crowns, jewels, medieval statuary, paintings and even cannon balls fired on the town and the church by Henry VIII when he besieged Boulogne in 1544. There are paintings, statues, sculptures, relics, medals but for me those amazing drawings of saints on the walls, the Roman style decoration of the vaulted ceilings and columns are quite fascinating.

You don’t have to be religious to enjoy this place, it’s theatrical, colourful and there is nothing else quite like it.

It’s a little bit chilly in the crypt so take a jumper with you and expect to spend around 1.5 – 2 hours to see everything.

Warm up afterwards in one of the cafés or restaurants in picturesque rue de Lille and wander round the ramparts of Boulogne soaking up the history – and the views.

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