On Mar. 14, a legend came to an end. Stephen Hawking, a theoretical physicist and cosmologist, died on Pi Day, which, coincidentally, was the birthday of another celebrated theoretical physicist, Albert Einstein. Hawking was considered one of the greatest scientists of his time, known for his innovative work with black holes, quantum theory, and relativity. He wrote at least 16 popular science books and was the subject of the 2014 movie The Theory of Everything.

Hawking was born on Jan. 8, 1942 in Oxford, precisely 300 years after the death of Italian polymath Galileo Galilei. His father was a respected medical researcher and biologist, while his mother graduated from Oxford University when very few women were able to attend college. You could say that he was born into a family of thinkers.

In school, like many other famous intellectuals, Hawking was recognized as “bright”, but was not a stellar student. He began attending University College at Oxford University at 17-years-old. While his father pressured him to study medicine to follow in his footsteps, Hawking instead chose to study physics. In 1962, Hawking graduated and entered Cambridge University to achieve a PhD in cosmology. However, in early 1963, Hawking was diagnosed with Amyotrophic Lateral Sclerosis (otherwise known as ALS or Lou Gehrig’s disease). Doctors estimated that he had no more than two years left to live; however, he lived 55 years more. Unfortunately, his disease caused his loss of mobility, and in 1985, his voice as well. After an emergency tracheotomy, Hawking completely lost the ability to speak. A device had to be constructed for him to speak through an electronic voice, using the movement of the muscles in his cheek. His disability makes all of his accomplishments all the more impressive.

Before being diagnosed with ALS, Hawking met Jane Wilde. They married and had three children before divorcing. Hawking left Wilde in 1990 to marry his nurse, Elaine Mason, in 1995.

As for his contributions to science, Hawking, having worked extensively with Albert Einstein’s Theory of Relativity and quantum theory, suggested that space and time began with the universe’s birth, and they will likely end with black holes. He also made great leaps forward in the study of black holes.

Hawking was a celebrity in the scientific world for his work, but he was also a famous author, even writing children’s books like George and the Big Bang. On top of that, Hawking made several appearances on television, in popular shows such as Star Trek: The Next Generation and The Big Bang Theory.

Hawking’s death was a great blow to the scientific community. The man defied his prognosis, lived past 70-years-old when he wasn’t expected to live to be 25-years-old, and bettered man’s knowledge of the universe during that time. As he once said, “Intelligence is the ability to adapt to change,” and he did just that.