Short answers, pulled from the story.
The term yuri was coined in 1976 by editor Ito Bungaku to describe female readers of a gay men's magazine in a column titled Room of the Lily Tribe. The flower known in Japanese as yuri became the unlikely flag for a genre that would eventually redefine how the world understands female intimacy in Japanese media.
Class S flourished in the 1930s as a literary movement depicting emotionally intense yet platonic relationships between upperclassmen and underclassmen in all-girls schools. This genre was pioneered by novelist Nobuko Yoshiya and viewed same-sex love as a transitory and normal part of female development leading into heterosexuality and motherhood.
The anime adaptation of Sailor Moon running from 1991 to 1997 introduced the world to Sailor Uranus and Sailor Neptune as the first mainstream coupling to feature a positive portrayal of a lesbian relationship in a magical girl series. The immense popularity of the series allowed it to be exported internationally and significantly influenced the shōjo and yuri genres.
The formalization of yuri as a discrete publishing genre began in 2003 with the launch of Yuri Shimai the first manga magazine devoted exclusively to the genre. This was followed by its successor Comic Yuri Hime in 2005 which actively curated a historical canon by retroactively labeling certain works as yuri.
The Rose and Candy archetypes defined the tragic stories of the 1970s and 1980s where a physically smaller character with lighter hair and a naive personality known as Candy bonds with a taller dark-haired character named Rose. These stories typically conclude with Rose dying to protect Candy from scandal and continue to influence contemporary yuri stories such as Bloom Into You.
Studies of yuri fandom reveal a complex demographic landscape where the first magazine to study the demographics of its readers was Yuri Shimai which estimated that women accounted for almost 70% of its readership. Later studies by Ichijinsha and academic researcher Verena Maser showed a more balanced split with some magazines seeing men account for 62% of the readership and others showing a 52.4% female to 46.1% male ratio.