Question: Was the original release of Empire Strikes Back called Episode V in 1980? Or was this added in a later re-release?

Did the original opening crawl actually start out with

> 
> *Star Wars  
> 
>  Episode V  
> 
>  The Empire Strikes Back*
> 
> 
> 

or just

> 
> *Star Wars  
> 
>  The Empire Strikes Back*
> 
> 
> 

or maybe even

> 
> *Star Wars  
> 
>  Episode II  
> 
>  The Empire Strikes Back*
> 
> 
> 

?

Answer: 
It was released as Episode V although Lucas toyed with it being Episode II in the beginning.

It is not quite the grand vision some would make out hence why the prequels contradict so much.
I saw The Empire Strikes Back in May 1980 and it indeed had the "Episode V:" prefix in the title of the opening crawl. It's true it had working titles of Star Wars 2 and other variations in other countries. The leak of the title in January 1978 by The Hollywood Reporter and official announcement by Lucasfilm a few months later in August explained this.

After the success of Star Wars in 1977 and announcement of a sequel some copies were updated to include the updated title "Episode IV: A New Hope" in the opening crawl in the early fall of 1977 but most people didn't see this new edit until the summer of 1978 when it was re-released the first time.