After a brief reconnaissance of the allied positions Junot correctly calculated that the Valongo Ridge was too formidable to be attacked successfully. He chose, therefore, to send a detachment far to the right beyond Ventosa where the heights were at their lowest, whilst Junot with the main body made a direct attack upon Vimeiro and the left-centre of Wellesley's position. The flanking detachment would be ideally placed to cut off Wellesley's only avenue of retreat.

Junot sent General Brennier with his brigade of four battalions plus the 3rd Provisional Dragoons and six guns along the Torres Vedras-Lourinha road to the north to turn Wellesley's left flank, and with the remainder of his force he moved upon Vimeiro. From his vantage point on the Valongo hill Wellesley saw Brennier's detachment marching off to the north and he immediately transferred three of his brigades from the Valongo ridge to the Mariano heights.

Having the advantage of interior lines the British troops had redeployed on the Marino ridge long before Brennier had completed his flank march. Only Hill's Division remained on the Valongo ridge.

Junot detected this movement of troops to the north-east and it induced him to make the fatal error of sending another brigade (Solignac's) to support Brennier.

The slope below Ventosa up which Solignac's brigade attacked.

The French commander thus divided his force into two halves separated by a distance of over two miles. By contrast the British brigades occupied a shorter front and if either wing of the British line was driven back it would push the allies into an even more compact position.

Order of Battle

French

Junot, after leaving 6,500 men in Lisbon and the Tagus to garrison forts, marched to engage the allies with his force organised as follows:

Division Delaborde

Brigade Brennier

3/2me Leger, 3/4me Leger, 1&2/70me de Ligne 3242

Brigade Thomieres

1&2/86me de Ligne, 4me Regiment de Suisse 1500

Division Loison

Brigade Solignac

3/12me Leger 3/15me Leger, 3/58me de Ligne 2838

Brigade Chariot

3/32me, 3/82me de Ligne 1394

Cavalry Division Margaron

3me, 4me 5me Provisional Dragoons 1888
1er Provisional Chasseurs, Squadron volunteer cavalry 100

Reserve

General de Division Kellermann

1er Regiment de Grenadiers 880

2eme Regiment de Grenadiers 780

Artillery

3 comp. Artillerie a pied, 1 comp. a cheval 700

Total 13,394 men and 23 guns

More Vimeiro

Vimeiro: Introduction
Vimeiro: The Defenders (and British OOB)
Vimeiro: The Attackers (and French OOB)
Vimeiro: The Battle
Vimeiro: Observations

Related

Busaco 27th September, 1810