Long before Alexander marched through, the Argandab valley was already old. The region the Greeks called Arachosia -- from the Old Persian Harauvatis -- had been significant since the Bronze Age, when the Helmand culture flourished at Mundigak. By the early first millennium BC, the settlement at what is now Kandahar had risen to prominence, its fortifications featuring inner and outer defenses with ramparts 14 meters wide, structures that predated all other known cities in the Iranian or South Asian regions. When the Achaemenid Empire absorbed the area in the mid-sixth century BC, they expanded and rebuilt the settlement, dividing it into quarters with inner walls and constructing a large citadel. Fragments of accounting tablets in Elamite -- the administrative language of Persepolis -- suggest the city served as a regional capital. Artifacts from its workshops turned up in the treasury at Persepolis itself, evidence that Arachosia was no provincial backwater but a place woven into the empire's economic fabric.

Alexander arrived in Arachosia in October 330 BC, fresh from the conspiracy trial that ended with the execution of his general Philotas. He was moving fast, chasing the remnants of Persian resistance under Bessus into Bactria, and he spent barely a month in the region before pressing on. None of the five principal ancient historians of Alexander -- Arrian, Plutarch, Diodorus Siculus, Curtius Rufus, or Justin -- mention that he founded a city here. The historian Peter Fraser noted that Arrian treated the entire region "almost as a grammatical afterthought." Yet other classical sources tell a different story. Isidore of Charax, in his Parthian Stations, recorded an "Alexandropolis, metropolis of Arachosia." Ptolemy, Ammianus Marcellinus, and Stephanus of Byzantium all reference an Alexandria in the region. Alexander left a garrison of 4,000 infantry and 600 cavalry somewhere in Arachosia -- enough to hold a city, even if no one thought to record exactly where.

After Alexander's death, Arachosia passed to his satrap Sybirtius. The Greek ambassador Megasthenes lived with Sybirtius before departing for the Indian court of Chandragupta Maurya -- a journey that underscores how this city sat at the hinge between the Hellenistic and Indian worlds. The Seleucids held it, then the Mauryans, then the Parthians. Each transition left its mark in the archaeological record: Greek coins, Buddhist-era structures, Islamic walls built atop classical foundations. The tell of Old Kandahar, in the western portion of the modern city, preserves these layers. Excavations by the British Society for South Asian Studies in the 1970s and again in 2008-2009 revealed that medieval Islamic fortifications followed the footprint of the ancient walls, suggesting a square or tetragonis town plan adapted to the site's unusual topography. No Greek buildings have been found, but coins, inscriptions, and graves testify to the Hellenistic presence.

Modern Kandahar sprawls around the ancient site, a city of over half a million people whose daily concerns have little to do with Macedonian conquerors. Yet the layers remain. The triangular portion of the citadel tell that adjoins the Greek-era town dates to the Buddhist period, a reminder that the city's cultural identity shifted as dramatically as its political allegiances. Pliny the Elder cited Alexander's bematists -- the distance-measurers who marched with his army -- referring to an "Arachosiorum oppidum," the town of the Arachosians. The local name persisted alongside the Greek one, as it always does when conquerors rename what they did not build. Kandahar has outlasted every empire that claimed it: Persian, Greek, Mauryan, Kushan, Islamic, British, Soviet. The fortress Alexander refounded was itself built on older foundations, and those foundations rest on Bronze Age soil. Every city is an argument about permanence, and this one has been winning for three thousand years.