It was not. The Quinn books were/are standard "wallpaper" historical romance and feature all white characters. AU historicals in Romance right now are starting to become more common - Courtney Milan's work has some examples, for instance a woman scientist coming to prominence, etc..

By "wallpaper" I mean the historical background is there but characters have some contemporary attitudes - it's a technical term romance writers/readers use themselves. Many readers prefer that style to romances involving more nitty gritty historical research and historical attitudes. [/genre neepery]