Thanks to my emails but also people who were participating today, I got an email from one of the key players that sent me some great leads and info to investigate! (Including a PDF of the report I was salivating over earlier.)
It turns out the angle brackets are at most from 1979, if not earlier. More to research!
This is the earliest appearance of < > I know of today, from 1979.
This thread might slow down, as next step will be some interlibrary requests!
This might be more interesting. <P1> and <P2>! <#> for styling! Excited to dig and learn more.
They are killing me. In the old article about the history of it that I just discovered, they are using… square brackets.
They really are killing me.
Fired some interlibrary requests. Wish me luck!
Is this going to go anywhere? Unclear. But I like this part.
I like scanning and putting up interlibrary stuff on Internet Archive.
This is the first one I got. Not sure yet if it’s going to help with the HTML bracket investigation, but maybe it’ll help someone else! https://archive.org/details/gca-standard-101-1983
Believe it or not, I’m still figuring out where HTML got its angle brackets.
But despite grabbing a lot of interlibrary items, I am not sure I’m getting any closer. I still have some ideas, but one involves going to a museum in Maine, which might take a while.
However, good news (for someone?): There are now over 40 papers and books I scanned that deal with history of markup. Enjoy!
https://archive.org/details/wicharytypewriter?tab=collection&query=subject%3A%22markup%22
Marcin Wichary