 Mercenary cavalry troops were also employed, including Thracians, Armenians, and even Berbers.No cavalry formation is unfortunately mentioned in the existent descriptions of cavalry battles, but all ancient Greek tactical manuals, including Asclepiodotus' Techne Taktike written in the 1st century BC, clearly and in detail describe the wedge and the rhombus formations, stating that they were in use at least at the time of their compilation as well as the more common square and rectangular formations.Thus, we have to accept the probability that they were used throughout the Hellenistic era.