Short answers, pulled from the story.
Tracy and Laura Hickman created the Ravenloft campaign setting in 1983 when they released the original module. They play-tested their adventure with a group of players every Halloween for five years under the title Vampyr before its official release.
The Ravenloft campaign setting was launched as a full-fledged product for AD&D 2nd Edition in 1990 with the Realm of Terror boxed set. This boxed set won the Origins Award in 1991 for Best Graphic Presentation of a Roleplaying Game, Adventure, or Supplement of 1990.
Strahd von Zarovich became the first Darklord of Barovia when the Dark Powers crafted the domain around him. He was originally a man who loved too fiercely and lost too completely before his transformation into a vampire.
Wizards of the Coast released Van Richten's Guide to Ravenloft on the 18th of May 2021. This sourcebook introduces other Domains of Dread to the edition and provides an overview of 39 Domains.
Viktra Mordenheim is the mad scientist who rules the Lamordia domain in Ravenloft. She is tormented by her inability to replicate the Unbreakable Heart device that keeps her reborn lover Elise alive.
Wizards of the Coast released a new edition of the Curse of Strahd module entitled Curse of Strahd: Revamped on the 20th of October 2020. This revision removed the portrayal of the Vistani as superstitious and removed reductive tropes through consultation with a Romani consultant.