Hetairenreiterei
Persian light cavalry took over the bulk of scouting duties when they became available to the Macedonian army following Gaugamela. The "sarissophoroi" then assumed a purely battlefield role as shock cavalry. It is possible that the "sarissaphoroi", due to their skill in wielding long lances and their extensive battle experience, were considered more valuable in the role of shock cavalry, especially after the departure of the Thessalian cavalry. In battle the "sarissophoroi" were usually placed on the outer flank of the Companion cavalry. Four "ilai", each 150 strong, of "sarissophoroi"/"prodromoi" operated with Alexander's army in Asia.