No reason to feel dumb—I didn’t immediately get the reference either. I saw that it was a reference to a legend about a golden apple from how it was the caption to a painting of a legend-looking-person holding a golden apple, so to answer your question I googled “golden apple legend”, found the wikipedia disambiguation page, and searched that for the legend that fit.
It’s a joking reference to the Apple of Discord story, wherein the goddess of discord Eris crashed a party and started the Trojan War.
Now I feel dumb, but at least I’m smarter. Thanx.
No reason to feel dumb—I didn’t immediately get the reference either. I saw that it was a reference to a legend about a golden apple from how it was the caption to a painting of a legend-looking-person holding a golden apple, so to answer your question I googled “golden apple legend”, found the wikipedia disambiguation page, and searched that for the legend that fit.