World History

Don't really know much about Frederick the Great, but I can tell you about another great- Alexander. He showed great tactical brilliance leading his father's cavalry in battle at age 16, and after his father's death, led a campaign of conquest east into Persia. He routinely defeated armies that dwarfed his in size, and by age 33 he had conquered and empire from Greece to the edges of India. He wanted to go further, but his soldiers refused to follow him.

Julius Caesar in another great military leader. At the siege of Alesia his army of 50,000 had built a wall surrounding an army of 80,000 Gaul's led by Vercingetorix in the city of Alesia. Caesar planned to wait until the Gauls starved to death or surrender, but discovered that a relief force of over 200,000 Gauls was on it's way. Most generals would have withdrawn facing those kind of odds, but not Caesar. He instead constructed another wall around the city, but facing the opposite direction. He was able to prevent the relief army from breaking in, and Vercingetorix's army from breaking out. The relief force eventually retreated after suffering several defeats, and Vercingetorix later surrendered.

Spartacus: Managed to lead a force of thousands of escaped slaves from several different countries and who spoke different languages. He kept this force intact and forged them into an army, melting down their chains of slavery and reforging them into swords and spears. He ran rampant around Italy for three years and made Rome tremble before he was finally defeated.