In Ptolemaic Egypt, the cavalry forces were led by a "hipparchos", who commanded a "hipparchia". The "hipparchiai" were divided into "ilai", then into "lochoi" and then into "dekades" (sing. "dekas", a file of 10 men). "Hipparchiai" fall into two categories. There were five known "hipparchiai" in the 3rd century, of which the 4th and 5th are known to have been in existence in the 2nd century BC. Other than these, there were four "hipparchiai" of lower status known by 'ethnic' names; the Thessalians, Thracians, Mysians and Persians. These probably were not actual cavalry troops from those ethnic groups, but more like the Tarantine cavalry mercenaries who did not need to be from Taras to be called thus.