There were many superstitions about chameleons in the lands they came from…so IMHO it’s not likely many people kept them as pets…
https://www.kapama.com/rangerblog/the-stories-behind-chameleons-in-african-culture-and-folk-tales/
As
@Andrew1283 said people who went to the chameleons’ native lands likely were fascinated by them and tried to take some home.
There were a few people studying them in the 1800’s. You might find this interesting…
http://www.anthonyherrel.fr/publications/Tolley & Herrel 2013 Chameleon Book.pdf
I started keeping them in the 80’s as did a few other people on here…but they were being kept in Europe and other places before Instarted keeping them.
The C.I.N. was the first regular publication I know of that people could learn about them from.
IMHO…ADCHAM was the first good forum where people learned about how others were keeping them. You might be able to find the actual forum using the Way Back Machine….but here’s the remnants of the website…
https://www.adcham.com/
The Chameleon News e-zine was another good source of information in that time….
http://www.chameleonnews.com/Home.html
You might want to see this…
https://www.chameleonbreeder.com/podcast/ep-87-history-of-veiled-chameleons-in-captivity/
I‘m sure this isn’t the answer you were looking for. I’ll see what else I can find.