What happened
The Persian commanders concentrated at the Granicus to meet the invasion. Memnon of Rhodes is said to have advised a scorched-earth withdrawal instead, and to have been overruled by satraps unwilling to see their own provinces burned.
The Persians drew up with cavalry along the far bank and the Greek mercenary infantry behind. Arrian reports that Parmenion advised waiting until dawn and that Alexander attacked at once.
The Macedonians crossed at an angle under fire and forced a bridgehead. The fighting on the bank was a cavalry melee in which Alexander was nearly killed; Arrian reports that Cleitus the Black saved his life by cutting off the arm of a Persian about to strike him.
The Persian cavalry broke. The Greek mercenaries, left standing, asked for terms; Alexander refused, surrounded them and killed or enslaved them.
Tactics
An opposed river crossing is among the hardest operations in pre-modern warfare, and the Macedonians attempted it against cavalry holding the far bank. The reported solution was to cross obliquely so that the line arrived formed rather than piecemeal, and to lead with a strong force that could absorb the first shock. The Persian dispositions have been criticised since antiquity for putting cavalry where they could not charge and infantry where they could not fight.
Consequence
Western Asia Minor was opened, and the Greek cities of the coast changed hands. Alexander sent three hundred panoplies to Athens as a dedication on the Acropolis, with an inscription naming the Greeks 'except the Spartans' — a political act as much as a religious one.
Location
The river Granicus in the Troad
Modern: The Biga Çayı, north-western Turkey
The river is identified; the crossing point is not. The channel has migrated across its floodplain since antiquity.
Open questions
Was the attack immediate or at dawn the next day?
Arrian describes an immediate assault across the river in the late afternoon. Diodorus describes a crossing at dawn the following day against an unprepared enemy. The two cannot be reconciled. Arrian's sources are closer to the events; Diodorus's version is tactically more sensible, which is itself an argument in both directions.
Primary sources
Arrian, Anabasis of Alexander 1.11-16
The principal narrative, drawing on the eyewitness accounts of Ptolemy and Aristobulus.
Diodorus Siculus, Library of History 17.18-21
An independent tradition differing from Arrian on the timing of the attack.
Plutarch, Life of Alexander 16
Preserves additional detail on the fighting at the bank.
How to read the evidence labels
- Evidence level: Documented
- Supported by a named primary text or by excavated material evidence.
- Evidence level: Probable
- Supported by strong inference that most specialists accept.
- Evidence level: Disputed
- Substantial specialist disagreement exists; competing readings are stated.
- Evidence level: Literary
- Belongs to poetic or mythological construction rather than to history.
- Evidence level: Mythological
- Belongs to shared religious or mythic tradition rather than to any single text.
- Evidence level: Unknown
- The available evidence is insufficient to decide.
These labels describe the status of the evidence, not our confidence in a conclusion. A claim marked Literary is not a claim we doubt; it is a claim about what kind of thing a poem is.