These lines beginning at Bouchain on the Schelde, were continued along the Sanset and the Scarpe to Arras, and thence along the Upper Scarpe to Canche.

They were defended by redoubts and other works in such a manner, that Villars judged they were impregnable, and called them the _Ne plus ultra_ of Marlborough.
This nobleman advancing within two leagues of the French lines, ordered a great number of fascines to be made, declaring he would attack them the next morning; so that Villars drew all his forces on that side, in full expectations of an engagement.

The duke, on the supposition that the passage of the Sanset by Arleux would be left unguarded, had ordered the generals Cadogan and Hompesch to assemble twenty battalions and seventeen squadrons from Douay and the neighbouring garrisons, to march to Arleux, where they should endeavour to pass the Sanset.

Brigadier Sutton was detached with the artillery and pontoons, to lay bridges over the canal near Groulezen and over the Scarpe at Vitry, while the duke with the whole confederate army began his march for the same place about nine in the evening.

He proceeded with such expedition, that by five in the morning he passed the river at Vitry.