Not to be confused with King's Field II, which was released as "King's Field" in North America and Europe.
There was a small country called Verdite surrounded by a deep forest, encircled by fog and whirling winds. In ancient days, when a great battle was fought and many were dying, Verdite was saved by a person who then disappeared into the forest. Only the forest's drifting fog knew who this person was... The citizens called their savior the Dragon of the Forest and built a sanctuary and honored this person there. Eventually, only a legend remained and the Sanctuary was changed into the Royal Graveyard and all was silent. But, the legend says, "Someday the Dragon of the Forest shall return, bearing Magical Artifacts." However, the time has not yet come and the Sanctuary sleeps deeply...
Source: Wikipedia, "King's Field", available under the CC-BY-SA License.
King's Field was never published outside of Japan.
King's Field II was released as "King's Field" in North America and Europe since it was technically the first playable entry for those regions.
King's Field III was then released as "King's Field II" in North America and Europe.
King's Field IV in Japan, was re-titled to "King's Field: The Ancient City" in North America and Europe.