It is often said that Alexander's army made him great - but his murdered father, Philip of Macedon, made the army great. Using professional soldiers, not a citizen-based militia, Philip created different types of military units which gave him diversified strength. Infantry, cavalry, foot soldiers who employed extra-long spears (called a sarissa), and elite foot guardsmen (called hypaspists) all made the Macedonian army a formidable fighting machine.
Solidifying his position soon after taking power, Alexander marched south into Greece and freed Greek cities from Persian rule. Heading north to Gordium (the capital of ancient Phrygia), he made relatively short work of a famous legend. Whoever untied the Gordian Knot, it was said, would rule the world. Alexander approached the problem in a different way. He undid the knot by simply slashing it with his sword, then unraveling it.
His conquests were just beginning.