"In 1480 Jean BALHAN, founder and grain merchant, lived on rue du Château (a house located at No. 31, which in the 17th century became the Auberge du Cadran in which La Fontaine met his friends Racine and Boileau). He bought the remains of a small castle built in 1120 by Count Thibaut II the Great and converted into a fortress: Fort Saint Jacques. The fort disappeared in 1429, sacked by the English. BALHAN had a square tower 33 meters high and topped with a slate roof in the shape of an octagonal spire ending in an open lantern.
To the east, the tower is flanked by two round turrets with hexagonal roofs and covered with slate. Corners are surmounted on the platform by two small pyramids which serve as a sort of wedge for the arrow. The turrets are pierced with narrow openings allowing the firing of the musket and arquebus. The lantern's weather vane represented "Fame". Inside, a beautiful winding spiral staircase serves the three floors. From the upper landing we enter one of the turrets. The chapel is the highlight of the monument. A historian calls it the chapel of the Count of Champagne. This chapel is Gothic in its vault and the bases of its trefoil windows and Renaissance in certain details of its ornamentation.
We can still see a niche which housed a statuette of Saint Barbara, above the entrance door. Two columns of a pretty design supported an altar stone in the form of a console. Above the ribs of the vaults rises a canopy of quite particular composition. Two angels sculpted in profile, with outstretched wings, support a shield whose relief figures constitute, except that of the lamb which is in the center, a real enigma for archaeologists.
Above, a medallion bearing the image of a character that we have tried in vain to identify: perhaps the owner of these mysterious coats of arms. On each side of the medallion crawl and grimace apocalyptic beasts. Behind a background of drapery in a lace arch an "Ecce Homo" raises its painful image.
To the right of the altar a door opens onto the second turret. In the 17th century, mass was still celebrated in this sanctuary.
From the chapel we go up to the watchman's room, which is notable only for a rather beautiful stone fireplace from the 16th century. This room is difficult to access because of the enormous plank cage which protects the mechanism of a clock.
The tower is topped by a campanile. The big bell, called Jean Balhan's, is the biggest in the city. This bell placed in the belfry served to warn the inhabitants of invasions close to enemies (very numerous until the 17th century), of fires and of summons to urban assemblies where the citizens of Château-Thierry discussed their interests and those of the city."