After completing its preparations in the leisurely manner of the previous generation, Brunswick's army crossed the French frontier on 19 August 1792. The Allies readily captured Longwy (23 August) and slowly marched on to besiege Verdun (29 August), which appeared more indefensible even than Longwy. The commandant there, Colonel Beaurepaire, shot himself in despair, and the place surrendered on 2 September 1792. Because this left the path to Paris wide open, radical revolutionaries in Paris and other cities panicked and started the September Massacres (2–7 September), killing hundreds of prisoners suspected of royalist sympathies and being in league with the enemy.