The minor battle of Baisieux of 29 April 1792 was the first battle of the War of the First Coalition, and marked the start of twenty three years of warfare. It came only nine days after the French had declared war on Austria on 20 April, and ended in a humiliating defeat for the armies of revolutionary France.
The declaration of war had followed the appointment of a new French government in late March, with Charles Dumouriez as minister of foreign affairs. Dumouriez believed that the presence of a French army would encourage the people of Belgium (then the Austrian Netherlands) to rise against the Austrians, and so ordered General Théobald Dillon to advance from Lille towards Tournai.
Dillon was given 5,000 men, most of them regular cavalry from the old Royal army, but reinforced by a number of volunteers. Dillon himself was a member of the liberal aristocracy that had helped produce the revolution, although by 1792 he was already out of step with the increasingly radical government in Paris.
Tournai was believed to be lightly defended, but the Austrian army was known to be advancing towards the French borders, and so Dillon had put in place plans for a tactical retreat if his force ran into overwhelming enemy forces. At Baisieux, roughly half way between Lille and Tournai, Dillon's advance guard ran into some Austrian artillery. Although this artillery was not part of the main Allied army, rumours quickly spread through Dillon's force that they were facing the feared Austrian invasion force (it would be another four months before the Allies actually advanced towards Lille).
Dillon issued the pre-planned orders for a tactical retreat. The professional cavalry, which had already lost many of its original officers to emigration, turned and fled. Dillon was caught up in the rout, and took shelter in a peasant's hut. The peasant believed that he had a traitor in his house and alerted the local garrison at Douai. Dillon was arrested, taken back to Lille, and murdered by the mob in an early indication of the fate that would befall a number of unsuccessful or unlucky French generals in the early years of the war.