Organization began in February 1808, with the best units of the disbanded Portuguese Army, including the elite Legion of Light Troops.

During the crossing of Spain, many of its soldiers defected, returning to Portugal and joining the Portuguese resistance against the French occupation.

The Portuguese Legion took part in the French campaigns in Germany, Austria and Russia, suffering heavy casualties.

[citation needed] It fought at the battles of Wagram, Smolensk, Borodino (Moscow) and Berezina.

[1] The Legion was disbanded on 5 May 1814, with only about 1,000 of its original 9,000 soldiers surviving and returning to Portugal.