Leonhard Euler was born in Basel, Switzerland, to Paul Euler, a pastor, and Marguerite Brucker. His father had some mathematical training and initially intended for Leonhard to follow in his footsteps and become a clergyman. The young Euler showed early promise in mathematics, captivating his family and peers with his quick mind and problem-solving skills.

At the age of 13, Euler enrolled at the University of Basel. While studying theology at his father's insistence, he pursued mathematics in his free time. His mathematical talent quickly became apparent, and he gained the attention of Johann Bernoulli, a prominent mathematician who recognized Euler's extraordinary abilities and became his mentor.

Following Bernoulli's recommendation, Euler was invited to join the St. Petersburg Academy of Sciences in Russia. Initially, he was appointed to the physiology department but transitioned to the mathematics department shortly after. This marked the beginning of a highly productive period in Euler's career, providing him with access to resources and collaborators that fostered his intellectual growth.

Euler experienced a severe fever that led to near-complete blindness in his right eye. While various theories exist regarding the cause, it marked a significant turning point in his life, though it did not significantly diminish his mathematical output. He adapted his methods to rely more on mental calculation and dictation, a testament to his incredible memory and intellectual capacity.

Amidst political instability in Russia, Euler accepted an invitation from Frederick the Great of Prussia to join the Berlin Academy of Sciences. He spent 25 years in Berlin, during which he produced a large volume of work, including significant contributions to calculus, mechanics, and optics. However, his relationship with Frederick the Great was strained, with the king finding Euler socially awkward and preferring the company of philosophers.

After a period of increasing tension with Frederick the Great, Euler returned to St. Petersburg at the invitation of Catherine the Great. Despite deteriorating eyesight, he continued his prolific research and publication, relying heavily on his sons and assistants to transcribe his work.

Euler completely lost his sight. Astonishingly, his mathematical productivity actually increased during this period. He dictated his mathematical ideas, relying on his phenomenal memory and sharp intellect. He even managed to produce several books and hundreds of articles, a feat that is truly remarkable.

Leonhard Euler died in St. Petersburg at the age of 76. He collapsed while discussing the recently discovered planet Uranus and suffered a brain hemorrhage. His death marked the end of an era in mathematics. His collected works comprise over 850 books and articles, solidifying his place as one of history's most prolific and influential scientists.