The Free On-line Dictionary of Computing (30 December 2018):

SIMULA I

    SIMUlation LAnguage.

   An extension to ALGOL 60 for the Univac 1107 designed in
   1962 by Kristen Nygaard and Ole-Johan Dahl and implemented in
   1964.  SIMULA I was designed for discrete simulation.  It
   introduced the record class, leading the way to data
   abstraction and object-oriented programming languages like
   Smalltalk.  It also featured coroutines.

   SIMULA's philosophy was the result of addressing the problems
   of describing complex systems for the purpose of simulating
   them.  This philosophy proved to be applicable for describing
   complex systems generally (not just for simulation) and so
   SIMULA is a general-purpose object-oriented application
   programming language which also has very good discrete event
   simulation capability.  Virtually all OOP products are derived
   in some manner from SIMULA.

   For a description of the evolution of SIMULA and therefore the
   fundamental concepts of OOP, see Dahl and Nygaard in ["History
   of Programming Languages".  Ed. R. W. Wexelblat.
   Addison-Wesley, 1981].

   (1995-03-29)