Theodore Rothstein was born 1871 in the Imperial Russian city of Kovno, Vilna Governorate (present-day Kaunas, Lithuania), the son of a Jewish family. Rothstein left Russia in 1890 for political reasons and settled in Britain. He worked as a journalist in the area of foreign policy for The Tribune, the The Daily News, The Manchester Guardian, and became a member of the National Union of Journalists. Furthermore he was active in London as a correspondent for some radical Russian newspapers. Rothstein also wrote articles for Die Neue Zeit, the organ of the Social Democratic Party of Germany (SPD), which represented the direct way of a consistent Marxism and in which took place debates regarding Marxism and socialism.