Short answers, pulled from the story.
Milan was founded around 590 BC by a Celtic tribe belonging to the Insubres group and the Golasecca culture, who named it Medhelanon. The Roman consul Gnaeus Cornelius Scipio Calvus conquered the settlement in 222 BC, after which it was latinized to Mediolanum.
The name derives from the Celtic Medhelanon, combining medhe- meaning 'middle or center' and -lanon, the Celtic equivalent of the Latin word for 'plain,' giving a meaning of 'settlement in the midst of the plain.' The Romans translated this directly with their version Mediolanum, from medio (in the middle) and planus (plain).
Milan and its metropolitan area account for about 20 percent of Italy's GDP, and the city hosts Borsa Italiana, Italy's main stock exchange, along with the headquarters of eight Fortune 500 Europe companies. The metropolitan region recorded a GDP of around 228 billion euros in 2024, making it the wealthiest province in Italy by total and per-capita GDP.
Leonardo da Vinci lived and worked in Milan from 1482 until 1499. He was commissioned to paint the Virgin of the Rocks for the Confraternity of the Immaculate Conception and The Last Supper for the monastery of Santa Maria delle Grazie. He also redesigned and improved the city's system of navigable canals, the navigli.
The Edict of Milan was issued by the Emperor Constantine in AD 313 from Mediolanum, granting tolerance to all religions within the Roman Empire. Constantine was in the city to celebrate his sister's wedding to the Eastern Emperor Licinius. The edict opened the path for Christianity to become the dominant religion of the Empire.
Milan's fashion industry grew rapidly in the postwar decades: exports valued at 726 million lire in 1952 had risen to 72.5 billion by 1955. By the 1980s, internationally recognized houses including Armani, Prada, Versace, Moschino, and Dolce and Gabbana were all headquartered in the city, and Milan Fashion Week became one of the most important events in the global fashion calendar.