The GRU first predecessor in post-tsarist Russia was created on October 21 , 1918 under the sponsorship of Leon Trotsky , who was then the civilian overseer of the Red Army ; it was originally known as the Registration Directorate ( Registrupravlenie , or RU ) .
The GRU 's first predecessor in post-tsarist Russia was created on October 21 , 1918 under the sponsorship of Leon Trotsky , who was then the civilian overseer of the Red Army .