Verichrome Pan dates from sometime in the mid 1950s, I think. I know I was using it in 1957 - 1958, but I'm not sure when it was introduced. It came along with a new Plus-X and Tri-X and with the introduction of thin emulsion films by both Kodak and other manufacturers.
Before Verichrome Pan we had Verichrome, an orthochromatic film designed for amateur cameras. Verichrome was around in various forms for a very long time, at least since the 1920s. In the late 1940s it was rated at ASA 50 speed (roughly ANSI 125). It was not a terribly impressive film except for one thing - its extraordinary latitude. It was a multilayer film, and it was very tolerant of overexposure. As far as I can tell, Verichrome was never available as sheet film, although it it was made in all roll film sizes and in film packs, which contained thin film (like roll film) cut to sheet film sizes.
Verichrome Pan was a huge step forward over the Verichrome it was designed to replace. First, it was panchromatic, so it rendered scenes more realistically. But it retained much of the latitude of Verichrome, so it could be used in non-adjustable cameras in most lighting situations. It didn't have quite the latitude of the old Verichrome, but it was close enough. It also had very fine grain and high sharpness, compared to the moderate grain and sharpness of its predecessor. This caused a dilemma for some photographers and for Kodak, since Verichrome Pan then competed directly with Plus-X. Plus-X had been the go to medium speed panchromatic film up until that time. It had less latitude than Verichrome (or Verichrome Pan), but it was very versatile for use in adjustable (and most of the time in non-adjustable) cameras. Now Verichrome Pan was available in rolls and packs, and many people preferred it to Plus-X. It had the same speed, about the same grain and sharpness, and better latitude. Oops. It wasn't long before Verichrome Pan film packs disappeared, although Plus-X packs continued until Kodak stopped making film packs.
I also miss VP. The long latitude gave its prints a certain look. Perhaps the best sheet film comparison was Royal Pan, although Royal Pan didn't have the latitude of Verichrome Pan. It was also quite forgiving about exposure, although quality did suffer if you didn't pay attention.