It was formed on 8 September 1799 in the Batavian Republic from Polish volunteers, mostly French prisoners of war from the Austrian Army.

As the King also felt reluctant to take financial responsibility for them, Napoleon reassigned them to quell the Haitian Revolution which was currently giving him problems.

After Stanisław Fiszer had turned down the command in favour of returning to Poland, Fortunat Bernard, a Frenchman, was appointed.

After a storm had thwarted an initial attempt to depart, the 3rd Polish Demi-brigade left Livorno on May 17, 1802, reaching Cadiz by July 11.

[1] Eventually combat casualties and tropical diseases (like the yellow fever) reduced the 5,280 strong Legion to a few hundred survivors in the space of less than two years.

However, Navarrez led some troops of the 86th Line Infantry Demi-brigade to their rescue, by which time only four were still alive, a total of thirty five having been killed.