The document discusses the Greek-Persian Wars and the Silk Roads. It describes how the Persian Empire controlled the Silk Roads in 500 BC but was defeated by the Greeks in battles at Marathon and Salamis as they tried to conquer Greece. It then discusses how Alexander the Great later invaded Persia from Macedonia and defeated them at the Battle of Gaugamela in 331 BC, gaining control of the Silk Roads. Finally, it notes that in the 21st century, Iran is again trying to gain influence over the region through Syria and Iraq, but faces opposition from an alliance between Arabs and Turks who both want greater individual control over the Silk Roads.