After Alexander's chain of victories, he began a campaign against local chieftains and warlords that stretched from Greece to as far as the region of Punjab in South Asia.

During his two decades on the throne, Philip II had unified[5] the poleis (Greek city-states) of mainland Greece (with Macedonian hegemony) under the League of Corinth.

[9] He also succeeded his father as head of the League of Corinth, a confederation of Greek states that were under the hegemony of Macedonia in order to combat the Achaemenid Empire.

[10] News of Philip's death roused many states into revolt, including Thebes, Athens, Thessaly, as well as the Thracian tribes to the north of Macedon.

[12] Before crossing to Asia, Alexander wanted to safeguard his northern borders and, in the spring of 335 BC, he advanced into Thrace to deal with the revolt, which was led by the Illyrians and Triballi.

The Persian cavalry turned and fled the battlefield, and the Greek mercenary infantry they held in reserve were encircled by the Macedonians and slaughtered; only around two-thousand of which survived, and were sent back to Macedonia for labor.

[21] Antipater, whom Alexander had left in charge of Macedon in his absence, had been given a free hand to install dictators and tyrants wherever he saw fit in order to minimize the risk of a rebellion.

[citation needed] After reaching Mount Taurus, Alexander's army found a stream that flowed from the mountain with water that was ice cold.

[10] After Alexander's forces defeated the Persians at the Battle of the Granicus, Darius took personal charge of his army, gathered a large army from the depths of the empire, and maneuvered to cut the Greek line of supply, requiring Alexander to countermarch his forces, setting the stage for the battle near the mouth of the Pinarus River and south of the village of Issus.

Darius was apparently unaware that, by deciding to stage the battle on a river bank, he was minimizing the numerical advantage his army had over Alexander's.

This surprised Darius who mistakenly elected to hold the wrong position while Alexander instructed his infantry to take up a defensive posture.

Alexander personally led the more elite Greek Companion cavalry against the Persian left up against the hills, and cut up the enemy on the less encumbering terrain, thereby generating a quick rout.

Tyre, the largest and most important city-state of Phoenicia, was located both on the Mediterranean coast as well as a nearby Island with two natural harbors on the landward side.

[citation needed] Alexander sent an envoy to Tyre, proposing a peace treaty, and asked to visit their city and offer sacrifices to their God Melqart.

The Tyrians politely told Alexander that their town was neutral in the war, and that allowing him to offer sacrifices to Melqart would be tantamount to recognizing him as their king.

Alexander began with an engineering feat that shows the true extent of his brilliance; as he could not attack the city from sea, he built a kilometer-long causeway stretching out to the island on a natural land bridge no more than two meters deep.

According to the Roman historian Quintus Curtius Rufus, Batis was killed by Alexander in imitation of Achilles' treatment of the fallen Hector.

"[10] They welcomed Alexander as their king, placed him on the throne of the Pharaohs,[10] giving him the crown of Upper and Lower Egypt, and named him the incarnation of Ra and Osiris.

He set in motion plans to build Alexandria, and, though future tax revenues would be channeled to him, he left Egypt under the management of Egyptians, which helped to win him their support.

[citation needed] The Battle of Gaugamela took place in 331 BC in what is now Iraqi Kurdistan, possibly near Dohuk,[26][27] and resulted in a decisive victory for the Macedonians.

After the Siege of Gaza, Alexander advanced from Syria towards the heart of the Persian Empire, crossing both the Euphrates and the Tigris rivers without any opposition.

Darius was building up a massive army, drawing men from the far reaches of his empire, and planned to use sheer numbers to crush Alexander.

[citation needed] After the battle, Parmenion rounded up the Persian baggage train while Alexander and his own bodyguard chased after Darius in hopes of catching up.

Darius, dying and chained to a baggage train being pulled by an ox, was lying next to a lone dog and his royal robes were covered in blood.

[30] Believing that, after his victory over the Uxians, he would not encounter any more enemy forces during his march, Alexander neglected to send scouts ahead of his vanguard, and thus walked into Ariobarzanes' ambush.

Oxyartes of Bactria had sent his wife and daughters, one of whom was Roxana, to take refuge in the fortress, as it was thought to be impregnable, and was provisioned for a long siege.

[citation needed] After the death of Spitamenes and his marriage to Roxana (Roshanak in Bactrian) to cement his relations with his new Central Asian satrapies, Alexander was finally free to turn his attention to the Indian subcontinent.

Omphis, ruler of Taxila, whose kingdom extended from the Indus to the Hydaspes, complied, but the chieftains of some hill clans, including the Aspasioi and Assakenoi sections of the Kambojas (known in Indian texts also as Ashvayanas and Ashvakayanas), refused to submit.

After gaining control of the former Achaemenid satrapy of Gandhara, including the city of Taxila, Alexander advanced into Punjab, where he engaged in battle against the regional king Porus, whom Alexander defeated in the Battle of the Hydaspes in 326 BC,[36][37] but was so impressed by the demeanor with which the king carried himself that he allowed Porus to continue governing his own kingdom as a satrap.

[41]Alexander spoke to his army and tried to persuade them to march further into India but Coenus pleaded with him to change his opinion and return, the men, he said, "longed to again see their parents, their wives and children, their homeland".