Not really relevant to this particular conversation. C# was commercially released in July 2000. The ECMA standardization committee was founded in September of the same year. Writing began in January 2003, and the standard officially adopted in June 2006. This is all described in the standard:
http://www.ecma-international.org/publications/files/ECMA-ST...
There's also a standard for CLI (Common Language Infrastructure), which is the underpinning of the .NET platform:
http://www.ecma-international.org/publications/files/ECMA-ST...