[Verginius Rufus]

The route to India via the Red Sea had been known since antiquity, but the route via the Cape of Good Hope was discovered by Bartolomeu Dias in 1488, only 4 years before Columbus' first voyage. Columbus did see both the South American and North American mainlands, but not on his first voyage.

If either Columbus or Vespucci wanted to talk to philosophers, they probably would have found contemporary Italian philosophers more interesting than Marcus Aurelius (who has been compared to Eeyore).

[decimon]

...they probably would have found contemporary Italian philosophers more interesting than Marcus Aurelius...

But you'd listen to Marcus because he was known to go medieval long before that was trendy.