The Battle of Bayonne (14 April 1814), the last major battle of the Peninsular War, ensued when the French garrison of Bayonne led by General of Division Pierre Thouvenot launched a sortie against a besieging force of British, Portuguese, and Spanish troops commanded by Lieutenant General John Hope.

It was fought after unofficial news of the abdication of French emperor Napoleon on 4 April had reached the opposing forces.

After initial success for the French, Allied forces drove them back inside Bayonne with heavy losses on both sides.

Although urged by his Russian ally to continue the campaign, the Marquess of Wellington refused to do so as long as the bad weather persisted.

[1] Obeying orders from Emperor Napoleon, Marshal Soult sent two infantry divisions and half his cavalry to the campaign in northeast France.

[3] By 14 February 1814, the weather cleared and Wellington's troops began moving east, prompting the French to fall back behind the Bidouze River.

After sending the division of Louis Jean Nicolas Abbé to reinforce the garrison of Bayonne, raising its strength to 14,000 men, Soult's field army counted 32,000 infantry and 3,800 cavalry.

Anxious that the French would discover his plans, Hope ordered Aylmer's and Campbell's brigades and España's division to launch probing attacks along Bayonne's southern front.

Meanwhile, 18-pounder long guns were mounted in the masked battery and when they opened fire, they drove off the French corvette Sapho and several gunboats.

The French had 2,700 soldiers in Bayonne's citadel, but incredibly, Thouvenot made no serious attempt to wipe out the 500 British troops on the north bank.

Instead, the citadel commander sent about 700 infantry to reconnoiter at dusk; these troops were hit by an accurate salvo of Congreve rockets and retreated.

[12] By dawn of 24 February, more Anglo-Allied soldiers made it across to the north bank and the flotilla of luggers and several Royal Navy warships were visible outside the mouth of the Adour.

[14] Though the French remained surprisingly passive while Hope reinforced his bridgehead, when the Allies tried to seize the Saint-Étienne suburb, they had a bitter fight on their hands costing almost 400 casualties.

The British Guards and the Portuguese had minor losses, but three King's German Legion (KGL) battalions sustained 328 casualties in the struggle, while the French lost 55 killed, 103 wounded, and 30–40 captured.

Wellington wanted to use the Adour estuary as a supply port, but merchant vessels proved unable to get across the bar at the mouth of the river.

From there, the line turned east, passed around the besieged fortress of Bayonne, and followed the north bank of the Adour to Port-de-Lanne.

However, Hope mistakenly believed that the garrison of Bayonne would soon be starved into surrender and only carried out Wellington's orders slowly.

On the night of 13 April, a French deserter gave the Allies notice of the planned sortie, but the strength of the attack would take them by surprise.

Most of Andrew Hay's brigade of the 5th Division was posted to the west at Le Boucau, to defend the bridge of boats.

[23] A feint attack was made against Anglet and Bellevue, while the main assault which numbered over 3,000 men, was launched north from the citadel.

Saint-Étienne was rapidly seized except one building where soldiers from the 38th Foot held out and the walled Jewish cemetery on the Bordeaux road.

The two columns from the citadel overran Stopford's picket line, capturing many men, and drove the Guards brigade to the north.

When Hope and his staff galloped from Le Boucau toward Saint-Étienne, they unwittingly took a route that the French troops had just seized.

[27] After finding Maitland's defenses intact, Howard rallied some of Stopford's troops and counterattacked the French near the Jewish cemetery.

[26] By 8:00 am the Allies had recovered all lost territory with minimal damage to fortifications as the siege guns had not been deployed in the battery positions.

[28][29][30][21] Historian Charles Oman suggested that the Allies' unusual 1:3 killed-to-wounded ratio could be due to most of the 233 recorded as captured having been wounded, then taken prisoner when the picket lines were overrun.

[32] Late on 12 April 1814, two officers, one French and one British, arrived at Wellington's headquarters at Toulouse to inform him that Napoleon had been deposed.

[34] Wellington called Thouvenot a "blackguard" because he believed the Frenchman knew that war was over and deliberately attacked when the Allies had relaxed their guard.

After agreeing to the armistice, Thouvenot announced, "I will not have the English treated like demi-gods, as they have been at Bordeaux, and I have put a stop to the foolish demonstrations which might have taken place here".

(3) If the commander sees that the besieging force is making progress, he can launch a sortie for the purpose of wrecking the siege works and damaging the artillery.