Father of Graph Theory

Leonhard Euler was born on 15th April 1707 in Basel, Switzerland.
Euler's discoveries greatly influenced the fields of mathematics and physics
His best known findings is the Euler Identity, which shows the relationship between fundamental mathematical constants and is often called the most beautiful equation in mathematics.

Euler’s most notable contributions are:

The Euler identity: eiπ + 1 = 0. The Euler identity is often called the most beautiful equation in mathematics. This formula shows the relation between five mathematical constants: e, i, π, 1, and 0. It has wide-ranging uses in mathematics and physics, including electronics.
Mathematical function notation: f(x), where f stands for “function” and the variable of the function (here, x) is enclosed within the parentheses. This notation is widely used today.