The war started because Helen was taken away by Paris and the battle began to try to get Helen back.
Sparta conquest of Messiaen Civilization began by depopulated by emigration of the Achaean to other states.
the 2nd Persian War (Xerxes) Battles of Thermopylae, Salamis, Plataea (spellings may vary) occurred during the Greece-Persian Wars, as King Xerxes I of Persia sought to conquer all of Greece.
The Greeks and Persians went to war with each other because of the existence of Greek colonies in Asia Minor that had become part of the Persian Empire.
The Peloponnesian War remodeled the entire Greek state. The Athenian empire, which was a stronger side prior to the war, was reduced to a mere vulnerable slave of Sparta. After the war, Sparta was the ruling state of Greece.
Alexander The Great went around at least half of the world because he wanted to conquer and take the world over.