sims was born in kennington, london, england. his parents were george sims, a prosperous merchant, and louisa amelia ann stevenson sims, president of the women's provident league. sims was the oldest of six children, who were exposed to their parents' cosmopolitan artistic and progressive friends, including suffragists. he grew up in islington, london, and his mother often took him to the theatre. he was educated in eastbourne and then hanwell military college and the university of bonn. he had begun to write poetry at the age of ten, and at bonn he wrote some plays, including an adaptation of "dr. wespe" by benedix. he completed his studies in germany and france, where he also became interested in gambling. in europe, he translated balzac's "contes drôlatiques", which was published in 1874 by chatto and windus; but it was considered too racy and was withdrawn, only to be reissued in 1903.