Sacred Band of Thebes

[Paullus Scipio]

Plutarch Pelopidas 18 The sacred band, we are told, was first formed by Gorgidas, of three hundred chosen men, to whom the city furnished exercise and maintenance, and who encamped in the Cadmeia; for which reason, too, they were called the city band; for citadels in those days were properly called cities. But some say that this band was composed of lovers and beloved........Gorgidas, then, by distributing this sacred band among the front ranks of the whole phalanx of men-at‑arms, made the high excellence of the men inconspicuous, and did not direct their strength upon a common object, since it was dissipated and blended with that of a large body of inferior troops; but Pelopidas, after their valour had shone out at Tegyra, where they fought by themselves and about his own person, never afterwards divided or scattered them, but, treating them as a unit, put them into the forefront of the greatest conflicts.

So, Hoplites, full-time professionals paid and maintained by the State - originally used scattered among the front ranks of the Phalanx as a 'stiffening' ( i.e. one every 3 or 4 Hoplites in a conventional phalanx, the whole front rank if formed 25 or more deep....)
Later, used as a united unit - an elite........