Philip II of the kingdom of Macedon was born as the youngest child. His elder brother was supposed to succeed the king or his father, and Philip II became a hostage of the Greeks at Thebes at the age of 15. As his brother died during war, however, he took power around the age of 20. With the throne on his head, the young king embarked on the reform to the Macedon forces. He trained invincible troops that would beat up the whole world for a century.
The Macedon forces used spears twice as long as Greek soldiers. It took two hands together to grab spears. They made smaller shields to hang them on the arm. Top agents were designated to get trained hard for a year as longer spears, albeit fatal, require sophisticated control and weigh a lot. Philip II probably realized what qualities make for top agents and strong troops while he trained soldiers dealing with the longer spears. He occupied the mountainous areas of Macedon and conscribed shepherds to form a battalion of soldiers. In a brutally cold and hot weather, they managed to march and slept in poor bedding. In other words, they possessed a strong sense of accomplishment.
The Macedon troops defeated Thebes, topping the whole Greek region. In preparation for his march to Persia, unfortunately, Philip II was assassinated. His son Alexander took over control of his father’s forces and successfully conquered Persia.
The reform by Philip II was not a result of his invention. Rather than that, he learned a new set of war tactics aggregated by Thebes while in hostage. Some of them were devised by generals of Athens and Sparta. The thing that Philip II came to realize was that Greek people were not aware of newly trained troops and they had no will to nurture them.
It is an obvious fact that any genius invention does not appear out of the blue or overnight. An invention always precedes another. Genius inventors or innovators are not a creator who makes something out of nothing but the one with insight who nimbly realizes something.