On 1 July 1766, at Abbeville, a young man of 18 years of age, François-Jean Lefebvre de La Barre was beheaded for having failed to show religious respect.

In applying the law, the judge committed him to have his bones crushed until he confessed his crime and denounced his accomplices, his tongue torn out, his right hand and head cut off, and their ashes thrown to the wind.

The three principals in the case said that they had expected the judgment, having "been tried and convicted of letting pass twenty-five steps of a procession without doffing the hat on his head, not genuflecting, singing an unholy song, and making reference to infamous books, among which can be found Mr. Voltaire's Dictionnaire Philosophique".

At the turn of the 19th to 20th centuries, with embattled public schools and the secularisation of institutions, which culminated in the 1905 French law on the Separation of the Churches and the State, La Barre became a symbol of the anticlerical battle.

This plaque reads En commémoration du Martyre du Chevalier de La Barre supplicié à Abbeville le 1er Juillet 1766 à l'âge de 19 ans pour avoir omis de saluer une procession ("In commemoration of the Martyr Knight La Barre tortured at Abbeville 1 July 1766 at the age of 19 years for having failed to salute a procession").

From 1907, the ceremony's point of departure was the Monument La Barre and it finished at the place of his execution, near the town hall.

For nearly sixty years, there was a joint ceremony of freethinkers, often coming from very far away, and the Department's workers' movements and secular organisations.