In the time of Julius Caesar there was a Gallic village named Bibrax where the Remis (inhabitants of the country round Reims) had to meet the onset of the confederated Belgae.

[4] Whatever may have been the precise locality of that battlefield, Laon was fortified by the Romans, and successively checked the invasions of the Franks, Burgundians, Vandals, Alans and Huns.

In about 847 the Irish philosopher John Scotus Eriugena appeared at the court of Charles the Bald, and was appointed head of the palace school.

After the fall of the Carolingians, Laon took the part of Charles of Lorraine, their heir, and Hugh Capet only succeeded in making himself master of the town by the connivance of the bishop, who, in return for this service, was made second ecclesiastical peer of the kingdom.

The citizens had profited by a temporary absence of Bishop Gaudry to secure from his representatives a communal charter, but he, on his return, purchased from the king of France the revocation of this document, and recommenced his oppressions.

Uneasy at the result of their victory, the rioters went into hiding outside the town, which was anew pillaged by the people of the neighbourhood, eager to avenge the death of their bishop.

In the latter stages of the 1337–1453 Hundred Years' War, Laon was captured by Philip, Duke of Burgundy; he relinquished control to his English allies, who held it until 1429 when it fell to Charles VII of France.

[8] Located in the middle of Aisne, Laon borders (from the north, clockwise) with the municipalities of Aulnois-sous-Laon, Barenton-Bugny, Chambry, Athies-sous-Laon, Bruyères-et-Montbérault, Vorges, Presles-et-Thierny, Chivy-lès-Étouvelles, Clacy-et-Thierret, Molinchart, Cerny-lès-Bucy, and Besny-et-Loizy.

One of the oldest churches in the city is St John the Baptist, in the nearby neighbourhood of Vaux-sous-Laon, which dates from the 11th through 13th centuries and is built in a mixture of Romanesque and Gothic styles.