This is a very common progression that is in fact equated with heroism and the "epic" sound we hear in so many soundtracks.
Assuming C is tonic:
In terms of Roman numerals, this is a
The chords you listed are
Which gives a scale collection of
C D Eb E F G Ab Bb C, which is no scale collection that I know of, so there's going to be some aspect of chromaticism involved. This can happen in one of two ways, both under the umbrella term of "mode mixture" or "borrowed chords":
- The piece is in C major (hence the E in the final chord), but "borrows" pitches/chords from the mode of C minor (hence the term "mode mixture"), which is where we get the Af and Bf chords. If you're in C major, you might want to clarify the Roman numerals to show these alterations:
- The piece is in C minor, so now the Af and Bf chords make sense, but the E in the final chord doesn't; so in this case, we just recognize it as a Picardy third, which just means we make the final chord major even though we expect it to be minor.
As for why it works so well: in the late nineteenth century, composers started playing around with just moving major triads around (we call this "planing"), and this is one of the sounds that stuck. In short, it's just lots and lots of major.