This is an irreverent marching song of the Duke of Wellington`s troops during the 19th Centuary Peninsular War (Spain, Napoleonic Wars). The words are Portuguese(?) NOTE: Marnot was an unsuccessful French General.

I believe I heard this song as an 1890`s French music hall song in a 1980s(?) British TV drama based either on a story by Guy de Maupassant or Sir Arthur Conan Doyle...

...The story line is of two young girls in a country orphanage, the plain one stays and the other one goes to live the life of a dissipated music hall singer in Paris, returning many years later to die of TB but as she "dies" she exchanges her body for that of her plain friend.

POSTSCRIPT: Just as a matter of interest, the lyrics to one of the versions of "Over the hills and far away" the one ascribed to "the Redcoats" is the theme song for the British made TV series "Sharpe"...

...and yes, "Sharpe" is an officer in a Light (infantry) Division in the aforesaid Peninsular War (as above).