Final answer:
Philip's success in Greece was due to his ability to develop a strong military, strategic tactics, and efficient management of conquered territories.
Step-by-step explanation:
The most important factor in the success of Philip II of Macedon in Greece was his ability to develop a formidable infantry and cavalry through military recruitment and training. By transforming common farmers into skilled soldiers, Philip was able to secure control of new territories in Thrace, which provided economic resources for military expansion.
Philip's tactical innovation, such as organizing nobles into elite cavalry units and reorganizing the infantry into a new phalanx, proved effective against both barbarian tribes and traditional Greek phalanxes. In addition, Philip's use of diplomacy and his symbolic leadership role in Greek culture helped manage his new conquest of Greece.
Overall, Philip's military reforms and strategic tactics, along with his ability to secure resources and manage conquered territories, played a crucial role in his success in Greece.