Capturing Amphipolis Philip turned toward the Aegean Sea and took up the peninsula of Halkidiki. The most powerful city on the peninsula was Olinf. Olinf led a confederation of cities of Halkidiki and stood in the way of ambitious Philip plans. At first, neither Athens, with whom Philip was at war from 357 BC, nor Olinf did not take the threat seriously. Each side had used the Macedonians for their own purposes and did not perceive them as a real force in Greece. Philip spent all easy. He tried to reassure the Athenians, and with Olinfom even an alliance.
Taking advantage of the war with the allies of Athens, Phillip quickly became Pydna and Potideyu. On the Thracian coast he founded a new city – Philippi. In the 50 – ies of the 4th century BC Philip was able to capture the gold mines of Pangaea. This allowed him to enter the monetary system, which was built on the simultaneous circulation of gold and silver coins exchanged for firm sets rates. Financial reform in Macedonia promoted the development of trade. A accumulation of large amounts of money played an important role in the subsequent military successes Macedonian army. But the main thing achievement at the time of Philip – it was a military reform.
He managed to create the most powerful and modern army at the time, which is tactically superior to any other army of the ancient world. The basis of this army was huge ponderous Macedonian phalanx, which consisted of 16-18 thousand men. In depth, it was up to 24 ranks, and its armament consisted Saris (spear) in length from two to six meters. Small Greek shields have been replaced by large rectangular shields, and helmets protect the head warrior. Light infantry were armed with bows and javelins, heavy cavalry also had in its arsenal, Saris. Considerable attention is paid Philip and development of the navy. In the second half of the 4th century BC Macedonian fleet consisted of 160 triremes. Throughout Macedonia at that time were built forts and roads were laid. Philip developed and Corps of Engineers.