A self - destructive scorched earth strategy was the price of the Portuguese victory .
The Province of Lower Beira was particularly devastated during the second Franco - Spanish invasion of Portugal ( July -- November , 1762 ) .
A self - destructive scorched earth strategy was the price of the Portugal victory .
The Province of Lower Beira was particularly devastated during the second Franco - Spanish invasion of Portugal ( July -- November , 1762 ) .