The combat of San Cristobal (20-22 June 1812) was a standoff between Wellington and Marmont that developed while the British were besieging the Salamanca forts, and that almost produced the major battle that Wellington was searching for.
On 17 June Wellington entered Salamanca, four days into his invasion of Leon. Marmont decided to concentrate his army twenty miles further to the north, but left 900 men to defend three forts within the city. Wellington left the 6th Division to besiege the forts, and moved his main army to a ridge at San Cristobal, four miles to the north.
By 19 June Marmont had gathered all but one of his divisions (Bonnet, who was on his way back from the Asturias), and on the following morning he advanced towards San Cristobal in three parallel columns. The British could see 18,000 infantry and 2,000 cavalry and suspected that more troops were close behind. The French drove in the British cavalry outposts north of the line, and at 4pm Wellington ordered his men to form their line of battle. The 1st Division was on his right, followed by the 7th Division, 4th Division, Light Division, 3rd Division and on the left the Portuguese under Pack and Bradford. The 5th Division, one brigade from the 6th and 3,000 Spanish troops under Carlos de Espana formed the reserve. In all Wellington had 40,000 infantry and 3,500 cavalry while Marmont had 28,000 infantry and 2,000 cavalry at the start of the standoff.
The French advanced to within 800 yards of the British lines at their closest, and something of an artillery dual developed. In the evening the French sent a regiment to attack the village of Morisco, in the right -centre of the line, at the foot of the heights. The 68th Regiment of the 7th Division held off three attacks, losing 50 dead and wounded, before being withdraw overnight by Wellington.
All of this led Wellington to believe that Marmont would attack on the following morning, and probably because of this decided not to take the chance to launch an attack of his own. During the day Marmont's last troops arrived, giving him another 10,000 men. That evening he held a council of war, in which he argued in favour of launching an attack on the following day. However Clausel and Foy both argued strongly against taking such a risk, and managed to convince Marmont not to attack Wellington. This attack would almost certainly have ended in disaster.
On the morning of 22 June Wellington attempted to trigger an attack. The 7th Division was sent towards Morisco, which now formed the closest part of the French line. The 1st and Light Divisions were ordered to support the attack if the French responded, but instead the French withdrew their skirmish line and prepared to defend the village. Wellington wasn't prepared to risk a general attack at this stage, and the fighting died down.
Overnight Marmont withdrew five miles east to Aldea Rubia, taking up a new position with his left wing almost on the River Tormes. Wellington decided to stay where he was until the forts had been captured, and those troops that had been withdrawn from the siege when a battle looked likely were returned.