Object Oriented Programming: Two Origins, One Paradigm

Object oriented programming organizes software around objects that bundle data with the procedures that act on it. This atlas records its origin as genuinely disputed. Simula gets credit for the first classes and inheritance in 1967, while Alan Kay was already using the term the same year while building Smalltalk, so the paradigm's birth date depends on whether the mechanism or the name is being dated.

Designed by Kristen Nygaard and Ole Johan Dahl and released in 1967, Simula is considered the first object oriented programming language. Its Simula 67 variant introduced objects, classes and inheritance, and it went on to influence C++, Java and Smalltalk directly.

Nygaard designed Simula with Ole Johan Dahl in the 1960s and is called a father of object oriented programming. The language he built is widely regarded as the first to hold the paradigm's core mechanisms, even though the name came later from someone else's project.

Built at Xerox PARC through the 1970s under Alan Kay, Smalltalk is the purely object oriented language, and Smalltalk-80 was the first version shared outside PARC, in 1981. It gave the paradigm its name and much of its familiar modern form, and it went on to influence Objective-C and Ruby.

Kay led the Learning Research Group at Xerox PARC that created Smalltalk, working alongside Dan Ingalls and Adele Goldberg. He was already using the term object oriented programming in 1967, the same year Simula was released, which is why the atlas records both projects as the paradigm's origin rather than picking one.

Bjarne Stroustrup extended C with object oriented, generic and later functional programming facilities while keeping C's low level memory control. The result became a dominant language for systems programming, game engines and performance critical software, and it carried the paradigm forward into Java, C# and Rust.

Born in Denmark on 30 December 1950, Stroustrup built C++ by adding object oriented features onto C, a decision that let a generation of systems programmers adopt the paradigm without leaving the language they already used.

James Gosling's language, developed from 1991 and first released as Java 1.0 in 1996, carried object orientation into enterprise, Android and web back end software through its write once, run anywhere portability. Java itself was influenced directly by C and C++.

Gosling invented Java, the language that took object oriented programming from research systems into the everyday software running on servers and phones worldwide.