Simplify the following text for a Grade 9 native English-speaking person.
Original: It is named after Bernhard Riemann , who in the memoir `` On the Number of Primes Less Than a Given Magnitude '' , published in 1859 , established a relation between its zeros and the distribution of prime numbers .
Simplified: It is named after Bernhard Riemann , who wrote about it in the memoir `` On the Number of Primes Less Than a Given Magnitude '' , published in 1859 .