His march had been delayed two days, by an attack made by Trant and Terence upon the advanced guard, as it was making its way through a defile.

A hundred prisoners were taken, with some baggage; and a serious blow would have been struck at the French, had not the new Portuguese levies been seized with panic and fled in confusion.

Trant was, consequently, obliged to draw off.

The attack, however, had been so resolute and well-directed that Massena, not knowing the strength of the force opposing him, halted for two days until the whole army came up; and thus afforded time for the British to concentrate, and make their arrangements.
[Illustration: Plan of the Battle of Busaco.] The ground chosen by Wellington to oppose Massena's advance was on the edge of the Sierra Busaco; which was separated, by a deep and narrow valley, from the series of hills across which the French were marching.

There were four roads by which the French could advance.