It is well known that :
if $n$ is an integer, $n\ge2$, having no divisor $d$ such that $1<d\le\sqrt n$, then $n$ must be prime.
My Questions :
Since when do we know this result ?
To whom should we attribute it ?
Any precise references would be appreciated.
A Brief History of Factoring and Primality Testing B. C. (Before Computers) by Richard Mollin (PDF link) makes two attributions.
To Ibn al-Banna, in application to the sieve of Eratosthenes:
To Fibonacci (in his Liber Abaci, first published in 1202), in application to primality testing: