I vaguely recall Symbian being adopted/developed(?) by Nokia. It's incredible how early Symbian was, but what's most remarkable is that it wasn't even Nokia's only shot at a smartphone OS, they also had Maemo.
It's a shame Nokia is now throwing away everything they know about Symbian. The new nokia OS is shockingly crap. Some functions straight out don't work and other functions such as T9 text are awful. It's a shame when you realise that their old Symbian phones work perfectly well and there was no need to change it.
Nokia hasn't been making phones for a long time. They license the name for HMD Global and the modern devices have nothing to do with Nokia itself.
The even older DCT3 generation of Nokia phones worked much better than Symbian ever did. Nokia 6210 is still a great phone if you only need to call and receive SMS. But anything with a color display from that era is really showing its age by now.