Who Was Prince Charlie Anyway?

[Nanook]

While some Savile Row tailors did (and still do) military tailoring, that work represented only a fraction of their everyday trade-- civilian clothing.

So developed Saville Row.

The short "riding coat" existed much earlier than the 1790s

One of the great inputs, beyond military, was equestrian fashion.

As for "le Petite Empereur" by 1814 Napoleon was tucked up on St. Helena, eating arsenic-laden wall paper, and having very little to do with influencing much of anything, let alone men's fashion.

I meant to type 1800s and not 1880s. I just am not allowed to edit anything I write here--- so the awkward policy of this forum towards me.

I'll merely point out that "trousers" in the from of trews, were worn fully half a century before the French Revolution.

Your missing the point of "fashion". The kilt, for example, was worn before the Scottish Romantic period but it was only during it and above all through the influence of, among others, the Highland Society of London that it came into its own as fashion. "Blue jeans" were worn since Jacob Youphes invented them but came into "fashion" (other than as working clothing) no earlier than the mid-1950s (Marlon Brando in "The Wild One" and a year later matched up with boots on James Dean in "Rebel Without a Cause") if not even the 1970s as mainstream fashion (the "designer jean").