Silver tetradrachm of Lysimachus showing the deified Alexander with the ram's horn of Ammon — Tetradrachm of Lysimachus (posthumous issue, c. 305–281 BC) with the deified Alexander wearing the ram's horn of Ammon — propaganda coinage, not a likeness.

Timeline

Every major date, each with a certainty label. Alexander's chronology is unusually solid for the ancient world — and unusually honest about where it isn't.

How to read the labels: Traditional the date ancient authors give; Narrative the conventional date from the source sequence; Anecdote attached to a story, not an archive; Fixed pinned by astronomy or contemporary records.

1. Birth at Pella — 20 July 356 BC

Traditional Plutarch (Alex. 3) gives the 6th of Hecatombaeon, conventionally rendered 20 July. The month is the ancient claim; the exact Julian day is modern conversion. The omens attached to the birth (the burning of Artemis’ temple at Ephesus) are legend.

2. Taming of Bucephalas — c. 344 BC

Anecdote Plutarch (Alex. 6) places it in Alexander’s youth, with Philip’s remark that “Macedonia is too little for thee.” No date is given in the sources; c. 344 is modern placement, and the story’s historicity is unprovable.

3. Tutored by Aristotle at Mieza — c. 343–340 BC

Narrative Plutarch (Alex. 7–8). The dates are inferred from Philip’s campaigns and Alexander’s regency in 340. See Alexander and Aristotle.

4. Regent of Macedon; Chaeronea — 340 / 338 BC

Narrative Alexander governed Macedon at sixteen during Philip’s Byzantium campaign (340) and commanded the left wing at Chaeronea (2 August 338 — the day is given by some sources, accepted by convention).

5. Philip II assassinated; Alexander becomes king — 336 BC

Narrative Murdered by Pausanias at Aegae during the wedding of Cleopatra. The month (October) is modern inference. Alexander was twenty.

6. Destruction of Thebes — autumn 335 BC

Narrative After Thebes revolted, Alexander stormed and razed the city. Diodorus (17.8–14), Arrian (1.7–9).

7. Crossing of the Hellespont; Battle of the Granicus — spring / May 334 BC

Narrative Alexander landed in Asia in spring 334; the Granicus was fought in the month Daisios (May). Arrian 1.11–16. See the three great battles.

8. Gordium and the knot — winter 334/333 BC

Narrative Alexander wintered at Gordium in Phrygia; the knot episode belongs here. Arrian 2.3; Plutarch, Alex. 18. See the Gordian knot.

9. Battle of Issus — November 333 BC

Narrative Fought in the month of Maimakterion; modern conversion gives November 333. Arrian 2.6–11; Diodorus 17.32–37.

10. Siege of Tyre; Egypt; founding of Alexandria; Siwa — 332–331 BC

Narrative Tyre fell after a seven-month siege (Arrian 2.15–24). Alexandria was founded in the winter of 332/331 (Arrian 3.1–2); the Siwa journey followed. The exact founding day is not recorded.

11. Battle of Gaugamela — 1 October 331 BC

Fixed The firmest date in Alexander’s life: Arrian (3.7) notes a lunar eclipse eleven days before the battle, and the eclipse of 20 September 331 BC is astronomically certain. A Babylonian cuneiform diary independently records the battle. See the three great battles.

12. Babylon, Susa, Persepolis; death of Darius III — 331–330 BC

Narrative Alexander entered Babylon in October 331 (Arrian 3.16). Persepolis was taken and its palaces burned in the winter/spring of 330. Darius was murdered by Bessus in July 330 (Arrian 3.21).

13. Bactria and Sogdiana; death of Cleitus — 329–328 BC

Narrative Three years of guerrilla war (Arrian 3.28–4.22). Cleitus was killed at Maracanda in 328 (Arrian 4.8–9).

14. India: Hydaspes; mutiny at the Hyphasis — 326 BC

Narrative The Hydaspes was fought in the summer campaigning season of 326 (Arrian 5.8–19). Bucephalas died in June 326. The Hyphasis mutiny followed (Arrian 5.25–29).

15. Return through Gedrosia; death of Hephaestion; Susa weddings — 325–324 BC

Narrative The Gedrosian desert crossing (late 325; Arrian 6.21–27). Hephaestion died at Ecbatana in autumn 324 (Arrian 7.14). The Susa weddings: spring 324 (Arrian 7.4).

16. Death at Babylon — 10/11 June 323 BC

Fixed The Royal Journals (preserved via Arrian 7.25–26 and Plutarch, Alex. 76–77) record Alexander falling ill on Daisios 18 and dying on Daisios 29/30 — conventionally 10/11 June 323 BC. A Babylonian astronomical diary confirms the year. The cause is unknown: see the death mystery.

Source notes

Chronological backbone: Arrian’s Anabasis, whose year-by-year structure is the most systematic; Diodorus 17 for an alternative year-count.
Gaugamela’s eclipse: Arrian 3.7.6; the 20 September 331 BC lunar eclipse is confirmed by modern retrocalculation and the Babylonian diary (Sachs–Hunger, Astronomical Diaries).
The Royal Journals (Ephemerides): quoted at length by Arrian (7.25–26) and Plutarch (Alex. 76–77); their authenticity is debated but they are the closest surviving thing to a contemporary day-by-day record.

Limitations

Month-level precision for most events is modern conversion of Macedonian/Attic month names; ancient calendars were lunar and intercalated irregularly.
The birth day (20 July) is a modern rendering of Plutarch’s month; it is traditional, not documented.
Army sizes, march distances, and casualty figures are excluded from this timeline — they belong to campaigns, where each number is sourced.