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John Tyler was born on March 29, 1790 and served as the 10th President of the USA from 1841-1845.

His Grandson, Harrison Ruffin Tyler (Born November 9, 1928), is still alive today.

According to Wikipedia, John died in 1862 and Harrison was born in 1928. So he never met his grandfather.

It makes me wonder - who is the oldest "directly-known" person? Maybe there's a better term for this. What I mean is, of all of the currently-living people, who is the person that one of them actually met who was born the earliest?

If you think about it, there are about a couple of hundred super-centenarians (110 or older) alive[1]. Surely at least one of them met a very old relative when they were young - for example, when I was 9, I met a great uncle who was 100 years old. Taking into account life expectancy, if you assume at least one of them has met someone 85 years older than them, that means this oldest "directly known person" would have been born at least 195 years ago (1829). Which means there’s a good chance someone alive has met someone born in the 1820’s.

[1] https://en.m.wikipedia.org/wiki/Supercentenarian#Incidence

> Maybe there's a better term for this.

Seems to be the rule used in Coco.

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