Richard Sharpe is a character created by Bernard Cornwell in a long series of books, all of which were titled Sharpe's <Something>. Sharpe was an orphan, and all he's known is the street and the army. At the beginning of the first movie (and book) he saves Wellington's life (technically "Sir Arthur Wellesley" at the time as he hadn't yet been given a title) when three French skirmishers pursue him and nearly kill him. Wellington says "You've done me a damn good turn, sir. And now I'm going to do you a damn bad one: I'm giving you a field commission" (not verbatim, but quite close). This is a promotion, but much worse than it sounds: in the British army at the time, the officers were "gentlemen" who bought their commission or were given it because of their titles, and the army was made up of men like Sharpe: commoners with no name and no means. As an officer, Sharpe was no longer accepted by the men of the army, but was also never to be accepted by the other officers who saw him as a "jumped-up guttersnipe." He has a fierce temper, an excessive sense of honour, a very good brain, and a knack for killing - and even more importantly a knack for surviving. He's an appealing character.

The books spawned a long series of TV movies made by ITV in the UK starting in 1993, with titles that generally matched the book's ... although the plots don't quite have a one-to-one relationship with the books. I'm told the books are very good: I've only binge-watched all the movies. The first 15 were made in three seasons of five each, each one exactly 1h41m and the DVDs at a rather odd display ratio of about 1.7:1 (rather than full widescreen at 1.78:1). The last two are oddities, made later, set in India, and showing Sharpe after his nominal retirement from the army.

• "Sharpe's Rifles" (1993) is the first and the best. As with most series, the plot in which the protagonist becomes a hero is the best (this is why Marvel retcons and tells origin stories over and over ...)
• "Sharpe's Gold" is one of the weakest, with Spaniards with Aztec practices hiding in the hills (and basically NOT Cornwell)
• "Sharpe's Regiment" sees Sharpe back in England for the first time on film, trying to track down his new regiment - which turns out to be something of an accounting fiction. Except that the colonels and generals who cooked the books aren't happy to have their fiction uncovered. But being in England, the feel of the movie is quite different, although Sharpe is still struggling to solve a mystery. I didn't like it much.
• "Sharpe's Justice" - post-war (but pre-Waterloo) he's back in England, and pitted against factory workers in the town where he was born - the people he came from
• "Sharpe's Challenge" (2006) - immediately clear it's different: it's the first in full widescreen, and has a run-time of 2:18 whereas every other one was 1:41. It's also one of the weakest, with heavy-handed dialogue and improbable and convenient co-incidences.
• "Sharpe's Peril" (2008) picks up days after "Challenge," with Sharpe and Harper's stay in India extended rather against their will. It's not Cornwell, but it's not too bad. 16:9, and we're back to 1h41m

I recommend watching the first, and possibly the second. My reluctance to recommend the rest comes in part from them being too dark for my taste (which probably isn't a problem for most people, it's a war after all), and a certain sense of sameness (despite generally good writing).