Symbian OS began as an operating system called EPOC, which was developed in the 1980s by a company named Psion. In 1998, in a joint venture with telephone manufacturers Nokia, Ericsson, and Motorola, Psion became Symbian, Ltd., and EPOC became Symbian OS.
In 2008, Nokia acquired Symbian, and the majority of Symbian OS's source code was released under an open source license. At the time, it was one of the largest open-source code bases ever released to the public.
In 2011, Nokia partnered with Microsoft and began offering Windows Phone as their primary smartphone OS. The Symbian OS was relegated to a niche franchise that was still maintained as a development platform, but on a much smaller scale. Maintenance of Symbian OS was then outsourced to the consulting firm Accenture.
As of 2014, developers are no longer able to publish new Symbian applications, but existing applications are still available for download.