Not so long ago I posted Simon and Kirby Firsts. What I had to say about Simon and Kirby first was a work in progress and hoped that my readers would correct any mistakes that I made. Well diligent Marty Erhart met my challenge and pointed out that there was an earlier Simon and Kirby story splash then the two I had reported on. So ”Ivan the Terrible” in Captain America #4 (June 1941) appears to be the first Simon and Kirby story spalsh. It had already been clear that Simon and Kirby were not the first to do a full page splash and in my previous post I reported the finding that the honor seem to go to Bob Kane and Jerry Robinson for a story from Detective #39 (May 1940). Well Marty beat that as well by pointing out that Siegal and Shuster had done a full page splash for a Slam Bradley story from Detective Comics #1 (March 1937). You can see it in Wikipedia. So kudos for Marty Erhart for his great work.
In my previous post I had also remarked that Simon and Kirby were not the first artists to do a double page splash as I had remembered an earlier example from a Ka-Zar story in Marvel Mystery Comics. However I no longer remember which issue it was. Well sleuth Brian Cronin took my imprecise memory and nailed it down in Comic Book Legends Revealed #309. It was Marvel Mystery Comics #11 (September 1940) that had the Ka-Zar story in question. So Ben Thompson was the first comic book artist to do a double page splash a year before Simon and Kirby. But not only did Thompson do a wide splash his was also a story splash. So Thompson takes that first away from Simon and Kirby as well!
As I have said before it was not the firsts that Simon and Kirby did that made them so important. It was how great they did everything and how influential they were to comic book history. But there do seem to be two firsts that Simon and Kirby still retain. They were the first to create a romance comic book (Young Romance #1 September 1947) and the first artists whose names were used on a cover to promote the comic (Adventure #80 November 1942, to be clear artist signatures do not count).