[Len Parker]

https://www.worthpoint.com/worthopedia/superb-revolutionary-war-era-dragoons-1801405922

[Matthew Amt]

Alarm bells going off. The design and tooled lines are very obviously to make it resemble a Roman lorica segmentata. Which of course was always described by early modern historians as "leather".

Every detail from Trajan's Column and other later Roman artwork is there: The horizontal lines to delineate the bands; the rounded ends of the bands; the "button" fasteners; the graduated, rounded ends of the "bands" on the shoulder flaps; the row of rounded flaps at the waist.

Either the maker/owner of this "armor" was SERIOUSLY into his neo-Classicism, or it's a costume piece. Or a deliberate attempt at fake "Roman armor".

IF there is documentation for soldiers the 18th century actually wearing such things (call me skeptical), then okay, *maybe*, but otherwise...

Matthew

[Len Parker]

I thought there was a chance it was spanish.
https://en.wikipedia.org/wiki/Soldado_de_cuera
https://commons.wikimedia.org/wiki/File:Dragon_de_cuera_.jpg
https://mhiggins.com/items/18th-century-spanish-colonial-leather-armor-cuera/

[Dan Howard]

Leather armour was a LOT thicker than the above example. You can stick a pencil through that.

[Matthew Amt]

[Philip Renne]

In support of the hypothesis that this represents the remains of a theatrical costume, I've seen similarly weird "buttoned" segmentata in paintings from the early 19th century depicting Roman soldiers-perhaps the models that posed for those pictures wore similar outfits to this.

[Graham Shearlaw]

That's not thick enough to protect against more then the wind and rain or sparks from musket fireing.
An yes it look likes a costume piece of Roman armour.