Research help on Fabriano Aurelius stationery?

[rkesey]

Hello, all. A friend I occasionally chat with about fountain pens and inks recently gifted me a box of vintage Fabriano handmade stationery in beautiful condition. I'd love to know more about it--he didn't remember where he'd come across it or even how long he'd had it, so I'm completely in the dark, and Google hasn't been much help. I'd especially like to have a better sense of its age. Has anyone come across this before? I'll add some pictures of the box, the envelopes and their watermark, the folded A4 sheets and their watermarks... Thanks in advance for any help!