The garrison repulsed a premature British attempt to storm the fortified convents on 23 June, but finally surrendered four days later after an artillery bombardment breached one fort and set another one on fire.

At the same time, the Emperor Napoleon lost interest in Spain as he turned his energies to his planned French invasion of Russia.

[4] On 13 June, Wellington's army crossed the Rio Águeda near Ciudad Rodrigo in three columns on a front 10 miles (16 km) wide.

The left wing included the 3rd Infantry Division and two independent Portuguese brigades led by Brigadier Generals Denis Pack and Thomas Bradford.

[7] When Marmont received news on 14 June of the Allied offensive, he immediately ordered his army to concentrate at Fuentesaúco, 20 miles (32 km) north of Salamanca.

[9] Brenier and Maucune and General of Brigade Jean-Baptiste Théodore Curto's light cavalry evacuated Salamanca and fell back to the rendezvous point.

Foy marched from Ávila far to the southeast, Clausel came from Peñaranda de Bracamonte to the southeast, Ferey started from Valladolid to the northeast, Thomières marched from Zamora to the northwest, Sarrut came from Toro to the north, and General of Brigade Pierre François Xavier Boyer's dragoons started from Toro and from Benavente far to the north.

Despite Napoleon's instructions, Marmont also called in General of Division Jean Pierre François Bonet's 6,500 men from the Asturias, but these soldiers could not arrive for nearly three weeks.

[8] Wellington's army counted 28,000 British and 17,000 Portuguese, and a division of 3,000 Spaniards led by Major General Carlos de España, altogether 48,000 men.

[10] However, Marmont preferred to wait until Bonet's division arrived so that his numbers would nearly equal his adversary's strength.

The French commander also hoped to be reinforced by 8,000 troops from General of Division Marie-François Auguste de Caffarelli du Falga's Army of the North.

Wellington set up his headquarters in the city while Major General Henry Clinton's 6th Division invested the forts.

In fact, the three convents were massively reinforced using masonry from the dismantled University buildings, oak beams, and earth.

South of San Cayetano was La Merced with two guns that prevented the Allies using the Roman bridge over the Rio Tormes.

[14] Having assembled his army, Marmont advanced toward Salamanca on 20 June, pushing back the Allies' cavalry patrols.

The heavy cavalry brigades of Major Generals John Le Marchant and Eberhardt Otto George von Bock were in reserve.

[15] Wellington expected to be attacked on the morning of 21 June, but Marmont initiated no action because the divisions of Foy and Thomières and one dragoon brigade did not arrive until the afternoon.

According to a letter he sent to Prime Minister Robert Jenkinson, 2nd Earl of Liverpool, Wellington hoped to stage another defensive victory like the Battle of Bussaco.

That evening Marmont held a Council of war in which Maucune and Ferey advised him to attack but Clausel and Foy persuaded him not to.

On 23 June, Wellington sent Hulse's brigade back to Salamanca and ordered Clinton to renew the siege of the forts.

[18] The early morning of 24 June saw a heavy fog, accompanied by the muted sounds of musketry and by the occasional thud of a cannon firing.

The British army commander ordered Lieutenant General Thomas Graham to take the 1st and 7th Divisions and Le Marchant's cavalry across the river at Santa Marta de Tormes and block the French thrust.

The French pressed ahead to the village of Calvarrasa de Abajo beyond which they found Graham's divisions deployed in a strong position.

Four howitzers were placed in the Cuenca battery and ordered to fire red hot shot into the roof of San Vincente.

A new fire broke out in San Vincente; it ignited the main store of planks and threatened to explode the gunpowder magazine.

The French commander asked for a truce, requesting a chance to communicate with Duchemin, and promising to surrender in two hours.

Duchemin asked for a three-hour truce, but Wellington repeated his earlier promise to storm the place in five minutes if no surrender was forthcoming.

On 7 July, careless handling caused a portion of the gunpowder to detonate, killing 20 civilians and some soldiers, and wrecking several houses.

Popham's naval squadron appeared in the Bay of Biscay and the Spanish guerillas began wreaking havoc in the north.

When, at dawn on 27 June, Duchemin signaled that he was still holding out, Marmont resolved on a desperate attempt to maneuver south of Salamanca.