Thessaloniki

City · 315 BCE · in Europe

Capital of Kingdom of Thessalonica (1206–1224), Empire of Thessalonica (1236–1246).

Chengdu (311 BCE): Capital of Shu Han (224–262), Cheng Han (306–346), Former Shu (911–925), and 1 more.
Ardabil (c. 307 BCE): Capital of Atropatene (307 BCE–165 BCE).
Ganzak (c. 307–165 BCE): Capital of Atropatene (307 BCE–165 BCE).
Seleucia (305 BCE – 165 CE): Capital of Parthian Empire (239 BCE–224).
Artashat (c. 326 BCE): Capital of Kingdom of Armenia (326 BCE–428).
Van (c. 326 BCE): Capital of Kingdom of Armenia (326 BCE–428), Kingdom of Vaspurakan (911–1021).
Tigranocerta (c. 326 BCE – c. 428 CE): Capital of Kingdom of Armenia (326 BCE–428).
Edessa (302 BCE – 1150 CE): Capital of Kingdom of Osroene (63 BCE–214), County of Edessa (1099–1150).
Kutaisi (301 BCE): Capital of Colchis (301 BCE–231 BCE), Kingdom of Georgia (1010–1122), Kingdom of Imereti (1468–1810).
Paris (301 BCE): Capital of Kingdom of the Franks (508–768), Merovingian Empire (710–717), Carolingian Empire (718–723), and 11 more.

Around the same time and place

Aristotle (384 BCE – 322 BCE): Philosopher and polymath, student of Plato and tutor of Alexander the Great, who founded the Lyceum and wrote on logic, biology, ethics and politics.
Alexander the Great (356 BCE – 323 BCE): King of Macedon who conquered the Persian Empire and reached India, spreading Greek culture across the Near East before dying in Babylon at 32.
Carthage (c. 814–146 BCE): Traditionally founded by Phoenician settlers from Tyre, Carthage grew into the capital of a maritime empire that dominated the western Mediterranean until Rome destroyed it.
La Tène culture (c. 450–50 BCE): Iron Age Celtic culture named after a site on Lake Neuchâtel, Switzerland, known for its flowing curvilinear art; it spread across much of Europe.
Plato (c. 428 BCE – 348 BCE): Athenian philosopher, student of Socrates and founder of the Academy, whose dialogues, including the Republic, shaped Western philosophy.
Alexandria (331 BCE): Founded by Alexander the Great on Egypt's Mediterranean coast, it became the capital of Ptolemaic Egypt and a leading centre of Hellenistic learning.
Euclid's Elements (c. 300 BCE): Euclid of Alexandria compiled the Elements, a 13-book treatise on geometry and number theory that remained the standard mathematics textbook for over two thousand years.
Archimedes (c. 287 BCE – 212 BCE): Mathematician and engineer of Syracuse who approximated pi, formulated the principle of buoyancy and the law of the lever; killed when the Romans took the city.