The Tardenois is today a natural region (région naturelle) of France. It is known among archeologists for the epipaleolithic culture known as Tardenoisian after its characteristic arrowheads, originally found at Coincy in the Tardenois in 1885. The etymology of "Tardenois" is not known.
Originally, the Tardenois was a pagus (subdivision) of the civitas (state) of the Suessiones. After the Gallic Wars (58–50 BC), the Suessiones were subjected to the Remi, who were loyal allies of the Roman Empire.
In the Middle Ages, it became a county (comitatus) under the Carolingians, subject to visits by missi dominici (lord's envoys). It is mentioned in 853 as the pagus tardinisus. The border between the dioceses of Soissons and Reims ran through it. In 858, King Charles the Bald appointed a certain Northmannus, possibly a former Viking, as count in the Tardenois. He was still count in 868, when he got into a conflict with the Bishop Hincmar of Laon that was settled by the king in his favour.Hincmar, archbishop of Reims, records around 870 that the Tardenois was under a count named Bertram, a relative of his, who exercised the bannum and held placita. The Tardenois was at that time a typical Carolingian county.