[1] When the Grande Armée left the shores of the English Channel to fight in the War of the Third Coalition, Rey was given command of the Camp de Boulogne from 1805 to 1808.

"[9] The army of the Marquess of Wellington shipped 40 heavy siege cannon and large quantities of supplies to the nearby port of Pasajes in early July.

Wellington assigned Thomas Graham, 1st Baron Lynedoch the British 5th Division and a Portuguese brigade to undertake the siege operation.

A heavier bombardment and attack pried the French defenders from the monastery two days later, but the Allied infantry gave chase and were bloodily repulsed with 200 casualties at the main defenses.

[9] Rey sealed off the breach with internal defenses, manned the nearby buildings with marksmen, and zeroed in his artillery on the threatened area.

Led by the Royal Scots, the main column splashed across the Rio Urumea estuary at low tide and assaulted the breach from the east.

When the incoming tide threatened to drown the many British wounded, Rey generously allowed his soldiers to leave their defenses and rescue them.

He also shipped in fresh troops and supplies through the leaky British naval blockade and sent his sick and wounded soldiers back to France.

[14] The final assault began at 10:55 am on 31 August when James Leith's 5th Division rushed the main breach from the south while Thomas Bradford's Portuguese brigade stormed the smaller one from the east.

After enduring the one-sided slaughter for nearly 30 minutes, both columns retreated to the base of the wall where the troops hugged the ground to escape the intense fire.

Still undefeated, Rey led his men in a house-to-house battle that finally ended when he and his remaining 1,300 troops took refuge in the La Mota Castle.

Ensconced in his hilltop castle, Rey held out against a 60-gun bombardment until 8 September when he finally ran up the white flag.

[18] As a reward for his meritorious services, Emperor Napoleon I of France promoted Rey to general of division in November 1813 even though he was a prisoner of war.