Answer:
The famous mathematician Johann Bernoulli (1667-1748) encouraged Euler, then a student at the University of Basel, to read advanced books in Mathematics after becoming aware of the Euler's talent on this subject.
Explanation:
Leonhard Euler (1707-1783) enrolled the University of Basel in 1720, at the age of thirteen (a fact not unusual at that time), where Johann Bernoulli was a math professor.
After giving some classes in elementary mathematics to young Euler, Bernoulli promptly understood that Euler had talent and determination to math, and then suggested him advanced mathematical readings and offered him private classes freely every Saturday afternoon on topics that Euler found unable to understand.
By the way, Euler's father, Paulus, a Protestant clergyman, was a friend of the Bernoulli family, and also received some math classes from another famous mathematician Jakob Bernoulli, the elder brother of Johann.
