This was followed in 1911 by Professor of Theoretical Physics at Karl-Ferdinand University in Prague. That same year, he was able to make preliminary predictions about how a ray of light from a distant star, passing near the Sun, would appear to be bent slightly, in the direction of the Sun, leading to the first experimental evidence in favor of his theory.
The following year, he moved Prague to Zurich the following year to accept a chair at the Eidgenössische Technische Hochschule in Zurich. It also began a new phase in his gravitational research, with the help of mathematician friend Marcel Grossmann. He called his new work the general relativity theory, which he was able to publish in 1915.
In 1914 he became a German citizen and was appointed Director of the Kaiser Wilhelm Physical Institute and Professor in the University of Berlin. The Einsteins divorced on February 14, 1919. Albert then married his cousin Elsa Loewenthal on June 2 of that year.
The Nobel Prize he received in 1921 was not for his relativity theories, but for 1905 work on the photoelectric effect. Other honors he received during these years include the Coley Medal of the Royal Society in 1925 and the gold Medal of the Royal Astronomical Society in 1926.
He remained in Berlin until 1933 when he renounced his citizenship for political reasons and emigrated to the United States, where he became Professor of Theoretical Physics at Princeton. He became a United States citizen in 1940, but retained his Swiss citizenship. In 1944, as a contribution to the war effort, he hand wrote a copy of his 1905 paper on special relativity, which he put up for auction. This raised six million dollars and the manuscript now resides in the Library of Congress.
Albert Einstein retired from his post at Princeton in 1945. In 1952. after the death of the first president of Israel, the Israeli government offered the post of second president to Einstein, which he refused. On March 30, 1953, he released a revised unified field theory.
Einstein died on April 18, 1955 in Princeton, New Jersey. He was cremated at Trenton, New Jersey at 4 pm that same day and his ashes were scattered at an undisclosed place.