Science is mourning the loss one of its greats, as John Forbes Nash Jr., the Princeton University mathematician whose life inspired the film A Beautiful Mind, and his wife, Alicia, died suddenly in crash Saturday.

Reports suggest the two were traveling in a taxi near their New Jersey home, when their driver lost control as he tried to pass a neighboring vehicle, crashing into a guard rail in the process. The couple was ejected from the car, leading police to believe they weren’t wearing seatbelts.

Widely regarded as one of the greatest mathematicians of the 20th century, Nash was best-known for his work on game theory, the science of decision making, and the Nash Equilibrium. Almost every facet of human life – relationships, politics, economics, law, religion, etc. can be modeled as a game, where one side’s decisions influence the other’s by showing a little more of their hand. Nash’s work drew from the idea that in any such game, there is a point at which neither side benefits by changing its strategy – an equilibrium – when they’ve learned all there is to learn about their opponent. This has grown to be one of the most important concepts in modern economic analysis, and researchers have used Nash’s work in numerous fields, including evolutionary biology and A.I. development.

“John’s remarkable achievements inspired generations of mathematicians, economists, and scientists who were influenced by his brilliant, groundbreaking work, and the story of his life with Alicia moved millions of readers and moviegoers who marveled at their courage in the face of daunting challenges,” Princeton University President Christopher L. Eisgruber said in an official statement. Nash’s outside-the-box thinking caught the eye of many a scholar. In fact, one of his recommendation letters for Princeton contained just one line: “This man is a genius.”

Eisgruber’s sentiments are being echoed hundreds of times over, as heartfelt messages continue to flood social media. Even actor Russell Crowe, who played Nash in the 2001 film, spoke up.

Stunned…my heart goes out to John & Alicia & family. An amazing partnership. Beautiful minds, beautiful hearts. https://t.co/XF4V9MBwU4

— Russell Crowe (@russellcrowe) May 24, 2015

Though Nash made it clear that A Beautiful Mind didn’t perfectly represent his life and work, having struggled for years with schizophrenia, he was proud that his experience could inspire those struggling with mental illness. Both he and Alicia are remembered not only by mathematicians and scholars, but by the millions of people who were touched by their story.

His death comes over two decades after he won the Nobel Prize, and just a week after he received the Abel Prize, another top honor in the field of mathematics. “While I don’t know how long I will live, or how much I will be able to do, at least I lived,” Nash said in a 2004 interview. He certainly did.

To learn more about John and Alica’s lives, read his full Nobel biography here.

Images: Wikimedia Commons