SIMSCRIPT is a free-form, English-like general-purpose simulation language conceived by Harry Markowitz and Bernard Hausner at the RAND Corporation in 1963. It was implemented as a Fortran preprocessor on the IBM 7090 and was designed for large discrete event simulations. It influenced Simula. Though earlier versions were released into the public domain, SIMSCRIPT was commercialized by Markowitz's company, California Analysis Center, Inc., which produced proprietary versions SIMSCRIPT I.5 and SIMSCRIPT II.5.