The sarissophoroi were a unit of light cavalry

Light cavalry

Light cavalry refers to lightly armed and lightly armored troops mounted on horses, as opposed to heavy cavalry, where the riders are heavily armored...

 in the army of Macedon

Ancient Macedonian military

The army of the Ancient kingdom of Macedonia was among the greatest military forces of the ancient world. It became formidable under King Philip II of Macedon and his son, Alexander the Great....

 and various Hellenistic states. They wielded a shorter version of the infantryman's (pezhetairos

Pezhetairos

The pezhetairoi were the backbone of the Macedonian army and Diadochi kingdoms. They were literally "foot companions" .The Macedonian phalanxes were made up almost entirely of pezhetairoi...

) lance, but also carried javelins so that they may harry an enemy from a distance. This, and their general Thracian provenance, make them akin to the prodromoi

Prodromoi

In ancient Greece, the Prodromoi were the skirmisher light cavalry. Their name means "moving before the rest of the army". They were equipped with javelins, argive shields, and cavalry sword...

 cavalry corps. Thracian sarissophoroi served under Alexander the Great in his conquest of Persia, and were also heavily utilized by his successors- against each other and the Romans

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

. Their main role was to ride alongside the Companion Cavalry

Companion cavalry

The Companions were the elite cavalry of the Macedonian army from the time of king Philip II of Macedon and reached the most prestige under Alexander the Great, and have been regarded as the best cavalry in the ancient world and the first shock cavalry...

 to protect them from enemy light cavalry or missile troops. They rarely wore body armor, but were often known to have worn a helmet; in most sources it is a Phrygian

Phrygian

Phrygian can refer to:*A person from Phrygia*Phrygian cap once characteristic of the region* Phrygian language*Phrygian mode in music* Phrygian Valley, a historic location in northwestern Turkey...

 helmet.

Considering that they carry the sarissa

Sarissa

The sarissa or sarisa was a 4 to 7 meter long spear used in the ancient Greek and Hellenistic warfare. It was introduced by Philip II of Macedon and was used in the traditional Greek phalanx formation as a replacement for the earlier dory, which was considerably shorter. The phalanxes of Philip...

, the sarissophoroi had a very powerful charge, devastating to an enemy formation's flanks and rear.