In March the princes and ambassadors who had been assembled at the Hague separated and scarcely had they separated when all their plans were disconcerted by a bold and skilful move of the enemy.
Lewis was sensible that the meeting of the Congress was likely to produce a great effect on the public mind of Europe.

That effect he determined to counteract by striking a sudden and terrible blow.

While his enemies were settling how many troops each of them should furnish, he ordered numerous divisions of his army to march from widely distant points towards Mons, one of the most important, if not the most important, of the fortresses which protected the Spanish Netherlands.
His purpose was discovered only when it was all but accomplished.
William, who had retired for a few days to Loo, learned, with surprise and extreme vexation, that cavalry, infantry, artillery, bridges of boats, were fast approaching the fated city by many converging routes.
A hundred thousand men had been brought together.

All the implements of war had been largely provided by Louvois, the first of living administrators.

The command was entrusted to Luxemburg, the first of living generals.