Parthenia (Soretta originally) is a country in Dragon Quest IV. It is the only place where a special kind of medicinal herb, the Feverfew, is grown. The castle town is dedicated to farming this herb. The last remaining herbs are in a nearby pantry, but are guarded by demons, to the dismay of the inhabitants.
The party visits Parthenia in Chapter 5, where they find that a drought has all but eliminated Feverfew from the area, though there is some in the Imperial Pantry of Parthenia. They also learn that Alena has gathered a small party of adventurers to seek out the Feverfew, but the group is unable to find the secret chamber at the bottom of the cave and is forced to return empty-handed. Luckily, the Hero and his party successfully locate the herb and give to Kiryl, healing him instantly.