Trying to remember a very old TV show. It was on in the early 80s, and set in about the 17th or 18th century; all I really remember is a lot of guys with swords fighting bad guys (possibly the Spanish, and they were French, but I'm not sure on that one). And the theme tune had the following lines in it:
"As long as we have done our best
And no one can do more".
Loved it at the time. Any ideas?