What year did Albert Einstein become a US citizen?

Albert Einstein (1879-1955) became a US citizen in 1940. He was born in Ulm, Germany.

He attended a Catholic elementary school until the age of 8 despite his family being Ashkenazi Jews. After that, he went to Luitpold Gymnasium (now known as the Albert Einstein Gymnasium), a secondary school until he left Germany 7 years later.

When his family moved, Albert stayed behind to finish school. After a few years, he began resenting the school's teaching methods and convinced them to let him go by using a doctor's note. He travelled to Pavia, Italy, to rejoin his family.

He renounced his German citizenship in 1896 to avoid military service. Five years later, he became a Swiss citizen, which he was for the rest of his life.

When Hitler came into power in 1933, Albert didn't go back to Germany. Because of his Jewish background, he settled down in USA and became a US citizen as well in 1940.

He wrote a letter to President Roosevelt about the potential development of "extremely powerful bombs" and suggested the US look into it. This led to the Manhattan Project and the nuclear bomb. Although he advised the study of bombs, Albert Einstein was a pacifist. He considered signing the letter his "one great mistake in life. The only justification was the danger that the Germans would make them."

When he was 76, he died of internal bleeding due to an abdominal aortic aneurysm. He took a draft of a speech with him to the hospital and continued to work until the end.