You know, it's funny. Some of the first comics I read were old Swamp Thing comics, around the time Alan Moore was writing the title, before the birth of the Vertigo line. I knew nothing about the character, and had no idea who Alan Moore was; the only other comics I had read up to then were Archie and Ninja Turtles. But I remember Solomon Grundy being featured in Swamp Thing, and mentions of Cyrus Gold, as a figure out of Grundy's past.
Since then I've read plenty of stories about Solomon Grundy, and plenty of stories that mention Cyrus Gold. Particularly Grant Morrison's Seven Soldiers, which makes Slaughter Swamp and the death of Cyrus Gold part of its cosmic mythology. And now there's that Solomon Grundy miniseries which deals with the life and death of Cyrus Gold.
So, you could say that Cyrus Gold has been a figure haunting the edges of the DCU in my mind for as long as I've been aware of the DCU. Cyrus Gold has always been there, mysterious, never shown on panel but referred to any number of times, some figure out of legend whose death set all sorts of events in motion. To read this, now, what is probably the first mention of Cyrus Gold in all comics history, gives me a strange feeling of nostalgia. As if I had spent my life tracing some long-buried history and had finally found its origin.