Possibly being overjoyed by the tales of mythical exploits of Heracles, Semiramis, the fabled queen of Assyria, Cyrus, King of Persia and so on, Alexander the Great set out from the tiny kingdom of Macedon for a daring adventure, unheard of in the entire civilized world. His theatre of war was vast, extending from out of the Danube River to beyond Indus in northwest India. If one takes the present-day geography into account, it included Asiatic Turkey, Syria, Palestine, half of Egypt, Iraq, Iran, Afghanistan, the Punjab, Sindh, Baluchistan and southern Turkistan – in all about 2,000,000 square miles with an estimated 50,000,000 people during Alexander's time. It covered every type of terrain: fertile plains, arid deserts, vast mountain ranges and great rivers. Besides the vast army under Alexander's veteran commanders, there were historians, botanists, geographers, medicine professionals – in short scholars of almost every description travelling alongside. They left behind a vast store of information of what they saw and heard in the strange lands in the course of their journeys.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/202/opening-the-way-to-india/.