Nation of Islam
In 1952, after his release from prison, Malcolm went to meet Elijah Muhammad in Chicago. It was soon after this that he changed his surname to "X". Malcolm explained the name by saying, The "X" is meant to symbolize the rejection of "slave names" and the absence of an inherited African name to take its place. The "X" is also the brand that many slaves received on their upper arm. This rationale led many members of the Nation of Islam to change their surnames to X.
In March 1953, the FBI opened a file on Malcolm, supposedly in response to an allegation that he had described himself as a Communist. Included in the file were two letters wherein Malcolm used the alias "Malachi Shabazz". In Message to the Blackman in America, Elijah Muhammad explained the name Shabazz as belonging to descendants of an "Asian Black nation".
In May 1953, the FBI concluded that Malcolm X had an "asocial personality with paranoid trends (pre-psychotic paranoid schizophrenia)", and had, in fact, sought treatment for his disorder. This was further supported by a letter intercepted by the FBI, dated June 29, 1950. The letter said, in reference to his 4-F classification and rejection by the military, "Everyone has always said ... Malcolm is crazy, so it isn't hard to convince people that I am."
Later that year, Malcolm left his half-sister Ella in Boston to stay with Elijah Muhammad in Chicago. He soon returned to Boston and became the minister of the Nation of Islam's Temple Number Eleven. In 1954, Malcolm was selected to lead the Nation of Islam's Temple #7 on Lenox Avenue in Harlem, and he rapidly expanded its membership.
He became known to a wider audience after a local television broadcast in New York City about the Nation of Islam. After that, Malcolm was frequently sought after for quotations by the print media, radio, and television programs from the U.S. and, later, around the world. In the years between his adoption of the Nation of Islam in 1952 and his split with the organization in 1964, he espoused the Nation's teachings, including referring to whites as "devils" who had been created in a misguided breeding program by a black scientist, and predicting the inevitable (and imminent) return of blacks to their natural place at the top of the social order.
Malcolm was soon seen as the second most influential leader of the movement, after Elijah Muhammad. He opened additional temples, including one in Philadelphia, and was largely credited with increasing membership in the NOI from 500 in 1952 to 30,000 in 1963. He inspired the boxer Cassius Clay to join the Nation of Islam and change his name to Muhammad Ali. (Like Malcolm X, Ali later left the NOI and joined mainstream Islam.)