*"How long ago..."
There's a meme going around about "if you got $5K a day since Columbus's voyage 'till today you'd still not be a billionaire." Conventional wisdom says he set sail in August 3, 1492, but an interesting discussion popped up in my FB post on how we don't actually know when he set sail; I believe the premise of the argument is that the year/date was documented Aug 3, 1492 but that relative date may be different in regards to if we were to travel back in time 192,548 days.
I've only ever heard 1492 and while there may be a discrepency between Julian/Gregorian calendars, it would be a matter of days/weeks, not to the tune of 20+ years (as it would have to be to make the meme's math wrong).
Can someone help with some clarification on the matter?
There would be a discrepancy of 10 or 11 days in 1492 if you actually travelled back in time. You'd need to use a proleptic calendar to figure out what the day is "for us". Otherwise since everyone (in Latin Catholic western Europe) was using the Julian calendar in 1492, for everyone at the time the date was August 3, 1492 and there's no need to convert anything.
Here's another recent thread that talks more about old calendar dates: https://www.reddit.com/r/AskHistorians/comments/d66skm/when_did_people_started_writing_dates_as_we_do/f0tp0gp/