Persia, the most advanced and militarily skilled empire of the time set its sight on greece. by developing what new advancements in technologies did greeks use to defend their empire against invaders such as persia?

Ancient Greeks invented the use of technology in warfare. It is the base of military superiority of the civilization of the West. The first such invention was the Phalanx which was used against the Persians. The Athenians produced very fast triremes. The Greeks in Sicily developed the first advanced catapults. In the period of Alexander the Great colossal siege engines were produced. Alexander introduced an army that could move very fast (even today very important) a fact which requires an organization and planning. The Greek Ptolemaic kings of Egypt produced very large ships. The wars of the Diadochi for the control of the territory conquered by Alexander the Great continued for many years. The Romans very fast acquired the Greek military technology and developed the most organized military system the world ever has seen. The small city states of Greece were intergrated in an Empire that could afford the loss of many thousands of soldiers in a battle or in catastrophical events. Pyrrhus of Epirus experienced this fact. Approximately 400000 Roman soldiers died in the Carthaginian war. Around 100000 Romans died in a storm off Cape Pachynus in 255 BC which destroyed a Roman fleet.