I can't remember if I saw it on Facebook, Instagram, or YouTube shorts, though if I'd lay money down, it would have been Instagram reels.
It was a video of an older gentleman suiting up in what I guess is a reenactor's kit for a cavalry unit known as a Curiassier. They were mounted cavalry that as their name suggests, wore curiasses, maybe more colloquially known as a breastplate.
In this video it uses an alternate spelling starting with a K, like Kuriasser I think, along with a date, I want to say either 1517 or 1617
The man had a rather nice grayish white mustache and beard combo.
He starts in a pair of trousers, then with a slight hop on his heels, the next piece of clothes is on, and this keeps going until his is fully equipped with his cuirass, sword, and pistol.
I'd love to find it again due to me wanting to possibly recreate it for a cosplay for an OC for a book series I fell in love with. Seriously, Go Read the Gods of Blood and Powder Saga from Brain McClellan, flintlock Fantasy needs more love as a genre.
Thank you in advance!!