Today, the Persian empires of Antiquity are still remembered as being famous for their expert use of cavalry forces. However, the textual, pictorial and archaeological evidence shows a slightly different picture, especially when the early Achaemenid period is considered. During the Greco-Persian wars, Persian riders had little chance to shine and were not able to show their full military potential against the Greeks. This paper examines the available sources and, through the evaluation of data, tries to answer some questions about the origins of (Persian) heavy cavalry and their presumed “invisibility” during this time. Their actual capabilities and close combat effectiveness are investigated, emphasising the parameters we associate with heavy cavalry and the use of body protection in combat. The primary question is, though, whether we can talk about “heavy cavalry” as a separate category during this period or not.