 The non-Irish privates were to be incorporated into the Prussian Regiment serving with the Army of Portugal.It was not until 11 April 1812 that they arrived at the regimental depot at Bois-le-Duc ( s’Hertogenbosch ) in The Netherlands.The First Battalion saw its first action at the Battle of Flushing in the Walcheren Campaign of 1809, suffering many casualties from malaria.