Hi all! I came across an odd and very bold claim while doing research for an alternate history project, namely that the Portuguese knew about South America before Columbus ever set sail (as early as the 1420s, in fact). I tracked down this (admittedly very old) article on JSTOR that seems to be the main source for this claim. https://www.jstor.org/stable/1773506?seq=1#metadata_info_tab_contents

I tried reading it, but a lot of it I didn't understand, and I couldn't seem to find more up-to-date scholarly discussion either supporting or debunking this claim. I would greatly appreciate any insight anyone here has on this. Thanks in advance!