He also mentions the Parthian Empire. It was formed by the eastern satrapies recusing themselves from Macedonian overlordship and restoring a purely Iranian empire. It defended itself successfully against Rome, even though Rome absorbed what was left of the Macedonian kingdoms. The dates of the Parthian Empire are 247 BC through 224 AD. Although Curtius may have been writing about an empire vanished in his own day, the most straightforward approach assumes that he wrote in a window, 63 BC (start of the Roman Empire) through 224 AD.