(The Earlier period started from the middle of fifth century B.C.) early period started from the third century B.C., middle period started from the first century B.C., end period started from the first century and lasted until the middle of third century.
（早期は紀元前5世紀半ば頃から）前期は紀元前3世紀頃から、中期は紀元前1世紀頃から、後期は1世紀半ば頃から3世紀の半ば頃まで続いたと考えられている。