Gargoyles: Dark Ages
Gargoyles: Dark Ages, often abbreviated to The Dark Ages or simply Dark Ages, is one of seven proposed spin-offs, a prequel to Gargoyles taking place in Wyvern, Scotland in the years between 971 and 994.
The show was initially pitched to CBS, but not picked up.  It was first mentioned on Ask Greg as early as 1998, and beginning in 1999 the art pitch was regularly presented at the Gathering of the Gargoyles as a treat for convention attendees. 
With the gargoyles in 10th century Scotland largely nameless, Greg Weisman planned to use names to designate characters for the writers, artists, animators, etc (such as he did with Othello, Desdemona, and Iago on Gargoyles and "Second", "Sacrifice", and "True" (along with many others) in the SLG comic). If that wasn't feasible, Weisman planned on having Prince Malcolm name every gargoyle with a biblical or mythological name, so that the humans in the series (and the audience watching it) could use those names while the gargoyles continued to ignore them. 
In late 1997, Greg Weisman wrote "Once Upon A Time There Were Three Brothers...", a piece of prose fiction that was later adapted and published with the comic, serving as a supplemental lead-in to the series.
At the 2008 Gathering, Greg Weisman revealed that he has a Dark Ages story in mind for the next six part Gargoyles miniseries. This story would be told after the conclusion of the Gargoyles: Bad Guys: Redemption story-arc, assuming the miniseries comics continue at that point.  In 2009, a possible name for the miniseries was revealed to be Dark Ages: Dream, and its story would cover "a substantial span of time". 
On April 19th, 2023, a solicitation from Dynamite Entertainment appeared on Amazon revealing the release of a comic book. On Voices from the Eyrie, Weisman clarified that the first arc in the series, Alliance, is not the same story he had in mind as a follow-up to Bad Guys.  The first issue, "The Reach" was released July 12, 2023.
Dark Ages is set at Wyvern Hill, Scotland in 971, with the beginnings of the alliance between the Wyvern Clan (then under Hudson's leadership) and Prince Malcolm, with Hudson and Prince Malcolm in the lead roles fighting the forces of King Culen. Goliath, Demona (at that point named "Angel", short for "Angel of the Night"), and the Coldtrio have supporting roles, as well as the Archmage (who is allied with Iago) as a villain (although presumably one whose true nature has not yet been revealed to the Prince).  Hudson's mate, "Verity", has a prominent role as well.  The trio are only children at this point, and would most likely have had a minor, possibly comic-relief, role.  The Illuminati would also have a role, likely as antagonists. 
The series will (if it continues long enough) cover the story of the Wyvern Clan between the foundation of Castle Wyvern in 971 to its fall in 994, including an account of how Princess Elena and Prince Malcolm died. (Greg Weisman has mentioned having strong ideas for how those events took place, but has not revealed them as yet.)  The Wyvern Clan's splintering into a second clan would have also been covered.