The spartans were a group of elite warriors from ancient greece, located on the island province of Sparta.
Spartan warriors are trained from infancy to be nothing but soldiers. They are to be perfect in every respect and aspect of war, and nothing else. Weaklings perish soon after birth; youth are taught to thieve and terrorize the slave class to harden them; young men are taught to nothing unless it has something to do with the arts of war - Even music and dance are tehre only to help keep step when marching and obeying orders. The result is a man who thinks nothing of danger, expects to win, and creates a sense of dread in his opponents.
Spartans fight in the traditional fashion of the hoplites, carrying a long thrusting spear and a large round hoplon shield. They, like the hoplites, were known to form a formation called a phalanx
(A close packed mass of men moving as one to crush their enemies)
There have been both a movie and graphic novel based on the most notable spartan accomplishment in written history.
300 spartan warriors (the personal guard of the spartan republic's current king Leonidas), held back the entire Persian army (massing up to 30.000) in a single tactical position, popularily called a "bottlehead". Eventually, after having held the persian army off for multiple days, devestating the persian morale, they died a martyr death. The martyr death was, without a question, a tactical move. After the death of King Leonidas and his men, all of greece united and fought back the persian army.
Imagine the terror inflicted on the Persian army as they saw 10.000 battle-ready spartans on the march, in regards to what a mere 300 had done.