28th Prince Eugene joined both the Dutch and Marlborough
before the town, taking up his headquarters at Froyennes, Marlborough
being at Willemeau, and the Dutch, under Tilly, already established on the
east of Tournai from Antoing to Constantin, just opposite Eugene, where
they threw a bridge across the Scheldt. By the evening of the 28th,
therefore, Tournai was invested on every side, and the great allied armies
of between 110,000 and 120,000 men had abandoned all hope of carrying
Villars' lines, and had sat down to the capture of the frontier
fortress.[2]

A comprehension of this siege of Tournai, which so largely determined the
fortunes of the campaign of Malplaquet, will be aided by the accompanying
sketch map. Here it is apparent that Marlborough with his headquarters at
Willemeau, Eugene with his at Froyennes, the Dutch under Tilly in a
semicircle from Antoing to Constantin, completed the investment of the
fortress, and that the existing bridge at Antoing which the Dutch
commanded, the bridge at Constantin which they had constructed, giving
access over the river to the north and to the south, made the circle
complete.

[Illustration: Sketch Map showing complete investment of Tournai.]

The fortifications of Tournai were excellent. Vauban had superintended
that piece of engineering in person, and the scheme of the fortifications
was remarkable from the strength of the citadel which lay apart from the
town (though within its ring of earthworks) to the south. The traveller
can still recognise in its abandonment this enormous achievement of Louis
XIV.'s sappers, and the opposition it was about to offer to the great
hosts of Marlborough and Eugene does almost as much honour to the genius
of the French engineer as to the tenacity of the little garrison then
defending it.

Two factors in the situation must first be appreciated by the reader.

The first is that the inferiority of Villars' force made it impossible for
him to do more than demonstrate against the army of observation. He was
compelled to leave Tournai to its fate, and, indeed, the king in his first
instructions, Villars in his reply, had taken it for granted that either
that town or Ypres would be besieged and must fall. But the value of a
fortress depends not upon its inviolability (for that can never be
reckoned with), but upon the length of time during which it can hold out,
and in this respect Tournai was to give full measure.

Secondly, it mus