The name Erlang was given in honor of the first scientist in the field of telecommunications: Agner Krarup Erlang (1878-1929)
Sometimes the name of language is also interpreted as Ericsson + Language = Er*lang*.
Between 1982 and 1986, in Ericsson labs were conducting research on the suitability of some existing programming languages in terms of creating apps for telecommunications needs, which required long-lasting and trouble-free operation with a large number of threads. The features of each language were analyzed, identyfiying potential problems that they could have caused. Despite the gradual narrowing of the set of considered languages, it was established that none of them meet the company's requirements, therefore it was decided to design a completely new language from scratch.
The author of the language is Joe Armstrong. He modeled Erlang on the Prolog language and wrote first Erlang interpreter in it. In 1990, Erlang was shown publicly at the ISS '90 conference, which resulted in increased number of users. But the first implementation of the language was so inefficent that in the late 1980s itself, work began on a faster version. It's final release took place in 1991. A Year later, the first book about Erlang was published and in 1993, Ericsson launched an independent department assigned with the development and distribution of the system and tools for it.
In 1998, Ericsson launched AXD301 switch with software that contained a milion lines of code in Erlang, which achieved a reliability index of 99.9999999% (that's the real number!), which meant that in a year of usage, the system could have at most 0.0315 seconds of downtime due to a failure. Shortly thereafter, Ericsson banned its affiliates from using Erlang in new products due to its proprietary nature. This caused a conflict between Ericsson and Armstrong, who left the company with the team. At the end of the same year, the Erlang implementation code was opened sourced and made available as free software. The ban was withdrawn later and Armstrong returned to work with Ericsson in 2004.