When was the first formula 1 car invented?

When was the first formula 1 car invented?
The Formula One car came from the issuance of the regulations detailing the Formula for the class.
So really there were several Formula one cars invented for the first race in 1947 and the world championship beginning in 1950
But... and there is always a Butt most people consider Pre-second world war racing to be Formula 1 also... but technically the current series is the only valid answer.