Agema (Greek: Ἄγημα), is a term to describe a military detachment, used for a special cause, such as guarding high valued targets. Due to its nature the Agema is most probably composed by elite troops.
The word derives from the Greek verb ago (Greek: ἄγω "to route, to drive"). It can literally mean a pack, a routing party and/or a detachment that has a single commander.
In ancient Macedonia, they were hypaspists and asthetairoi, and later argyraspids (silver shields). In the eastern Diadochi States (the Seleucid Empire, Ptolemaic Egypt, the Kingdom of Bactria) they were the infantry guards of the King. The eastern Agema guards wore bronze plate, Phrygian (or Thracian) helmet and Argive shield, and carried sarissa and short sword.
In Macedon, especially under Philip V of Macedon and Perseus of Macedon, the Agema formed an elite body within the corps of 'Peltasts'. This corps is not to be confused with the light infantry. The Macedonian Peltast corps was the equivalent of the Hypaspists in Alexander the Great's army. The Agema, as well as the Peltasts, according to Duncan Head, would fight in pitched battle as a conventional phalanx. Yet they may have used lighter equipment for forced marches.
The Agema had a full name, ‘The Agema of the Hypaspists’. The fact that there is an absence of them in detailed writings about the Seleucid campaigns may be due that they only retained the second half of their name and were the Hypaspists. They formed a crack force within the Infantry Guardsmen corps.