I've looked up the answer quite often, but I always forget who it was.*
I think of every schoolboy knows whenever I come across a list of contestants for some TV celebrity competition, or the latest features on a phone, or...
...well, the list of things that everybody knows (except me) is pretty-much endless.
Here's a recent example from The Telegraph of the 4th April:
'...a tariff war that bears some comparison with the famous Smoot-Hawley Act of the 1930s'
The Smoot-Hawley Act?
It occurs to me that sometimes ignorance might even be a sign of quite a well-lived life.
Word To Use Today: ignorance. This word can mean nastily ill-disposed in this part of Hertfordshire, England, but generally it's to do with not-knowing, from the Latin ignōrāre, not to know, from gnārus, knowing.
*I've just looked it up again, and it turns out that no one really knows who strangled Atahualpa (though Pizarro ordered his execution). Montezuma was imprisoned by the Cortes-led Spanish.