A picture of her is kept up on the wall in the house.
6m10s into episode 10, Richard refers to her as Aurelia while looking at her picture, revealing her given name.
A flashback in episode 18 has Richard remembering her introducing herself as Aurelia Hartwick, revealing her maiden name prior to marrying him. They met at a ball in the country and in the manga ,it reveals that she is an airhead and loves nature and animals and a woman of having no special skills. In the anime , there is an episode where it showed that she is terrible at dancing.
The reason Aurelia left was because the pressure of Society was causing her to become ill. She supports William and Emma's relationship but cautions Emma that it'll be hard work. When Emma replies that she'll do anything ,Aurelia smiles and says that she (Emma) is different than her.