Darius III in the context of "Satrapy of Armenia"

The wars of Alexander the Great were a series of conquests and military campaigns carried out by Alexander III of Macedon from 336 to 323 BC. They began with his conquest of the Achaemenid Empire, which was ruled by Darius III. After a series of victories over the Persians and the defeat Darius, he began a campaign against local chieftains and warlords that stretched from Greece to as far as the Indus Valley. At the time of his death, Alexander ruled over most regions of Greece and the conquered Achaemenid Empire, including much of Achaemenid Egypt.

Despite his military accomplishments, Alexander did not establish a stable empire, and his untimely death threw the vast territories he conquered into a series of civil wars known as the Wars of the Diadochi.

The death of Alexander the Great and subsequent related events have been the subjects of debates. According to a Babylonian astronomical diary, Alexander died in the palace of Nebuchadnezzar II in Babylon between the evening of 10 June and the evening of 11 June 323 BC, at the age of 32.

Macedonians and local residents wept at the news of the death, while Achaemenid subjects were forced to shave their heads. The mother of Darius III, Sisygambis, having learned of Alexander's death, became depressed and killed herself later. Historians vary in their assessments of primary sources about Alexander's death, which has resulted in different views about its cause and circumstances.

This is a chronological summary of the expedition of Alexander the Great into Asia against the Persian Empire of king Darius III, with indication of the countries/places visited or simply crossed, including the most important battles/sieges and the cities founded (Alexandrias). The events of the expedition are shown in chronological order. For each event is given, separated by:

1. date of event,
2. places/cities crossed, indicated by ancient name (present name, country),
3. regions, provinces or Persian satrapies of the places/cities crossed, with indication of their capital cities (where appropriate).

The ancient history of Afghanistan, also referred to as the pre-Islamic period of Afghanistan, dates back to the prehistoric era and the Helmand civilization around 3300–2350 B.C. Archaeological exploration began in Afghanistan in earnest after World War II and proceeded until the late 1970s during the Soviet–Afghan War. Archaeologists and historians suggest that humans were living in Afghanistan at least 50,000 years ago, and that farming communities of the region were among the earliest in the world. Urbanized culture has existed in the land from between 3000 and 2000 BC. Artifacts typical of the Paleolithic, Mesolithic, Neolithic, Bronze, and Iron ages have been found inside Afghanistan.

After the Indus Valley Civilisation stretched up to northeast Afghanistan, it was inhabited by the Iranic tribes and controlled by the Medes until about 500 BC when Darius the Great (Darius I) marched with his Persian army to make it part of the Achaemenid Empire. In 330 BC, Alexander the Great of Macedonia invaded the land after defeating Darius III of Persia in the Battle of Gaugamela. Much of Afghanistan became part of the Seleucid Empire followed by the Greco-Bactrian Kingdom. Seleucus I Nicator was defeated by Chandragupta Maurya and gave his daughter in a peace treaty. The land was inhabited by various tribes and ruled by many different kingdoms for the next two millennia. Before the arrival of Islam in the 7th century, there were a number of religions practiced in modern-day Afghanistan. Zoroastrianism and Ancient Iranian religions were practiced in western Afganistan (Khorasan and Herat). Hinduism and Buddhism was primarily practiced in regions of Eastern (Kabul) and South-Eastern Afganistan (Kandahar). The Kafiristan (present-day Nuristan) region, in the Hindu Kush mountain range, was not converted until the 19th century. They still follow the ancient Vedic religion (related to modern day Hinduism).

Alexander the Great (356 – 323 BC), a king of ancient Macedon, created one of the largest empires in history by waging an extensive military campaign throughout Asia. Alexander was groomed for rulership from an early age and acceded to the throne after the assassination of his father, Philip II. After subduing rebellious vassals, he invaded the Persian Achaemenid Empire in 334 BC. Alexander swiftly conquered large areas of Western Asia and Egypt before defeating the Persian king Darius III in battle at Issus and Gaugamela. Achieving complete domination over the former lands of the Achaemenids by 327 BC, Alexander attempted to conquer India but turned back after his weary troops mutinied. Following his death aged thirty-two in Babylon in 323 BC, his empire disintegrated in a series of civil wars fought between his followers.

Alexander founded numerous settlements during his campaigns, naming them after himself or close followers. These have been the subject of intense debate, as the accounts of ancient and medieval scholars differ wildly and are often contradictory. Plutarch provides the maximum estimate of seventy cities in his Life of Alexander, but most texts attest to between ten and twenty foundations. The Greek Alexander Romance lists between nine and thirteen cities, depending on the recension; the Syriac, Armenian, Hebrew, and Ethiopic versions of the Romance also record twelve or thirteen foundations. Persian sources such as al-Tabari, al-Dinawari, Hamza al-Isfahani, and Qudama ascribe between nine and twelve settlements to Alexander. Stephanus of Byzantium recorded around twenty settlements. Some authors additionally document the number of cities established in a specific area: for example, Strabo records that Alexander founded eight cities in Bactria. The accounts of Alexander's campaigns, primarily those of Arrian, Plutarch, Diodorus, Curtius Rufus, and Justin, provide supplementary evidence. Finally, the geographers Eratosthenes, Ptolemy, and Pliny draw upon the otherwise-lost evidence of Alexander's bematist distance-measurers.

Roxana (died c. 310 BC, Ancient Greek: Ῥωξάνη, Rhōxánē; Old Iranian: *Raṷxšnā- "shining, radiant, brilliant", Dari: روشنک, romanized: Rawšanak) sometimes known as Roxanne, Roxanna and Roxane, was a Bactrian or Sogdian princess whom Alexander the Great married after invading Persia and defeating Darius, ruler of the Achaemenid Empire.

Ardashir I (Middle Persian: 𐭠𐭥𐭲𐭧𐭱𐭲𐭥, romanized: Arda(x)šēr), also known as Ardashir the Unifier (180–242 AD), was the founder of the Sasanian Empire, the last empire of ancient Iran. After defeating the last Parthian shahanshah Artabanus IV on the Hormozdgan plain in 224, he overthrew the Arsacid dynasty and established the Sasanian dynasty. Afterwards, Ardashir called himself shahanshah and began conquering the land that he called Eranshahr, the realm of the Iranians.

There are various historical reports about Ardashir's lineage and ancestry. According to al-Tabari's History of the Prophets and Kings, Ardashir was son of Papak, son of Sasan. Another narrative recorded in Kar-Namag i Ardashir i Pabagan and Ferdowsi's Shahnameh states that Ardashir was born from the marriage of Sasan, a descendant of Darius III, with the daughter of Papak, a local governor in Pars.

The siege of Halicarnassus was fought between Alexander the Great and the Achaemenid Persian Empire in 334 BC. Alexander, who had no navy, was constantly being threatened by the Persian navy. It continuously attempted to provoke an engagement with Alexander, who would not oblige them. Eventually, the Persian fleet sailed to Halicarnassus, in order to establish a new defense. Ada of Caria, the former queen of Halicarnassus, had been driven from her throne by her younger brother Pixodarus of Caria. When Pixodarus died, Persian King Darius had appointed Orontobates satrap of Caria, which included Halicarnassus in its jurisdiction. On the arrival of Alexander in 334 BC, Ada, who was in possession of the fortress of Alinda, surrendered the fortress to him.

Orontobates and Memnon of Rhodes entrenched themselves in Halicarnassus. Alexander had sent spies to meet with dissidents inside the city, who had promised to open the gates and allow Alexander to enter. When his spies arrived, however, the dissidents were nowhere to be found. A small battle resulted, and Alexander's army managed to break through the city walls. Memnon, however, now deployed his catapults, and Alexander's army fell back. Memnon then deployed his infantry, and shortly before Alexander would have received his first defeat, his infantry managed to break through the city walls, surprising the Persian forces. Memnon, realizing the city was lost, set fire to it and withdrew with his army. Strong winds caused the fire to destroy much of the city. Alexander leading his army through the gates, ordered crews to extinguish the blazing structures and issued a decree that the citizens should not be harmed.