Did the Romans know there were other lands such as in China, Russia, India, Mongolia, Southern Africa, etc?

[Ludicus]

Wait, what? Why is he doubting its authenticity exactly?

I don't know exactly, but the mystical interpretation of some encounters is questionable.The Periplus is a Greek description. For instance, the word Gorillai appears nowhere else in Greek literature.Pliny identifies the Gorillai as gorgons or their heirs.Some scholars date the Periplus as early as the 5th century and others as late as the first, although both extremes rely on style and the testimony of later authors.
Here, enjoy,
Making Specimens in the Periplus of Hanno and its Imperial Tradition
Clara Bosak-Schroeder American Journal of Philology, Volume 140, Number 1 (Whole Number 557),Spring 2019, pp. 67-100 (Article)
(PDF) Making Specimens in the Periplus of Hanno and its Imperial

It is possible that an historical encounter between Hanno (or some-one else) and a great ape inspired the story preserved in the Periplus but the historicity of the account cannot be verified, nor would it necessarily have been known to ancient readers.

[Roma_Victrix]

I don't know exactly, but the mystical interpretation of some encounters is questionable.The Periplus is a Greek description. For instance, the word Gorillai appears nowhere else in Greek literature.Pliny identifies the Gorillai as gorgons or their heirs.Some scholars date the Periplus as early as the 5th century and others as late as the first, although both extremes rely on style and the testimony of later authors.
Here, enjoy,
Making Specimens in the Periplus of Hanno and its Imperial Tradition
Clara Bosak-Schroeder American Journal of Philology, Volume 140, Number 1 (Whole Number 557),Spring 2019, pp. 67-100 (Article)
(PDF) Making Specimens in the Periplus of Hanno and its Imperial

Thanks for sharing! The 5th century AD is most definitely wrong, though; that's way too late a date considering the historical details in the book and the various states that are mentioned in it. In either case it's rather silly to doubt the book's authenticity when there are plenty of other Roman authors who talk about India and how to get there. It also ignores the fact that there's like a mountain of Roman coins found in India going back to at least the reign of Augustus. India was most clearly the chief depot for the Roman purchase of Han-dynasty, Three Kingdoms, and Jin-dynasty era Chinese silk (with evidence that the Romans traveled as far as Vietnam and China for the same purpose, as I explained in a previous post).

[sumskilz]

I don't know exactly, but the mystical interpretation of some encounters is questionable.The Periplus is a Greek description. For instance, the word Gorillai appears nowhere else in Greek literature.Pliny identifies the Gorillai as gorgons or their heirs.

I read that P.E.H. Hair article after you posted it. It seems his main point is that it doesn't contain any information that can reliably be used regarding the history of sub-Saharan Africa, which was his main area of interest. That point is reasonable enough. Although, when he talks about subjects I know a fair bit about (the Canaanite languages and fauna in ancient Israel), he doesn't come across very well-informed. While that sort of sloppiness in research doesn't really undermine any of his main points in this case, it makes me wonder how many errors are in there regarding subjects I just don't happen to have much foreknowledge about. I thought his comment about the gorilla incident being sexist was kind of ridiculous. If anything, the fact that the females are said to be much more numerous than the males lends authenticity to the account. Did Hair really not know about the female biased sex ratios in Gorillas troops?

[Cyclops]

It's at least a stunning coincidence that an ancient explorer had an experience matching local conditions so closely. It makes the journey at least plausible.

Ditto the circumnavigation by the Phoenicians on behalf of the Egyptians. Herodotus ridicules the account because they describe the sun being in the northern half of the sky at the southern tip of Africa, which is a real observable phenomena: an odd way of confirming the story, including a detail you consider dubious (Herodotus really is the father of history). He also makes a fair guess at the cause of the Nile's annual flood, albeit with no direct knowledge.

The Hellenes and Romans had access to historical knowledge that Africa could be circumnavigated, as did their heirs the Portuguese.

[Roma_Victrix]

Ditto the circumnavigation by the Phoenicians on behalf of the Egyptians. Herodotus ridicules the account because they describe the sun being in the northern half of the sky at the southern tip of Africa, which is a real observable phenomena: an odd way of confirming the story, including a detail you consider dubious (Herodotus really is the father of history). He also makes a fair guess at the cause of the Nile's annual flood, albeit with no direct knowledge.

That kind of reminds me of Wang Chong, the eccentric Eastern Han period Chinese scientific thinker of the 1st century AD who accurately depicted the earth's hydrological cycle, but was kind of ignored by his contemporaries as a quack for criticizing Confucianism. Oh well!

[Cyclops]

That kind of reminds me of Wang Chong, the eccentric Eastern Han period Chinese scientific thinker of the 1st century AD who accurately depicted the earth's hydrological cycle, but was kind of ignored by his contemporaries as a quack for criticizing Confucianism. Oh well!

Babies and bathwater.

As I get older experience tells me more and more to disregard the idiot and listen to the rant. Turns out the idiot is usually me.