Dyson was born on 15 December 1923, at Crowthorne in Berkshire, England. He was the son of Mildred Lucy (Atkey) and George Dyson. His father, a prominent composer, was later knighted. His mother had a law degree, and after Dyson was born she worked as a social worker. Dyson had one sibling, his older sister, Alice, who remembered him as a boy surrounded by encyclopedias and always calculating on sheets of paper. At the age of four he tried to calculate the number of atoms in the Sun. As a child, he showed an interest in large numbers and in the solar system, and was strongly influenced by the book "Men of Mathematics" by Eric Temple Bell. Politically, Dyson said he was "brought up as a socialist".