Only one h1 per page?

Hi,

Recently, I made a talk about accessibility. I needed to talk about what
I'd learnt after making a lot of mistakes, because of a lack of knowledge.
I had a lack of empathy, because a lack of information/knowledge.
I read a lot of documentation about accessibility and I found the
recommendation about "only one h1 per page" in several resources, but now I
realize that W3C doesn't include it explicitly.

Now, I'm worry about it, because I also told it in my talk. I added a
disclaimer at the beginning of the talk: I'm not a specialist on
accessibility. But I would like to fix my errors if I told something wrong.

I've continued reading about it and I've found several articles (not in
WAI). They explain that it's a recommendation for previous versions of
HTML, not for HTML5. You don't have to worry about the order of the rest of
the headings if you add a <section> or <article>. In other words, you can
start by h1 again in an <article>, for example. I wonder if assistive
technology is ready for it.

Please, where can I find more information about this issue? Is it a valid
recommendation? Does this recommendation make sense with HTML5?

I'll write a post about my talk very soon, so I can take that opportunity
to clarify this issue. I can also fix my shared slides.

Thanks in advance for your time!

Best regards,

Raquel