Internazionale Milano was founded on 9 March 1908 in the Ristorante L'Orologio in Milan, when 44 dissatisfied members of AC Milan broke away in protest at that club's restriction on signing foreign players. The new club's name "Internazionale" (the international one) explicitly stated their philosophy of welcoming players of any nationality. Inter's blue-and-black stripes — earning them the nickname "Nerazzurri" — date to that founding meeting. The club has shared the iconic San Siro (Stadio Giuseppe Meazza) with AC Milan since 1947.
Inter's first European glory came under Helenio Herrera in the 1960s. Herrera's "Grande Inter" — featuring Sandro Mazzola, Giacinto Facchetti, Luis Suárez, Mario Corso and the catenaccio defensive system — won back-to-back European Cups in 1963-64 and 1964-65 along with three Serie A titles. The club's third European Cup came in 2009-10 under José Mourinho's historic Treble — Serie A, Coppa Italia and the Champions League sealed against Bayern Munich at the Bernabéu — featuring Wesley Sneijder, Diego Milito (whose two final goals decided it), Samuel Eto'o and Javier Zanetti, the captain. To this day, Inter remain the only Italian club to win the continental Treble.
The Suning era (2016-2024) restored Inter's domestic ambition under Antonio Conte and Simone Inzaghi — winning the Serie A in 2020-21 and 2023-24, the latter completing the second star (20 league titles). Despite Suning's eventual financial collapse leading to Oaktree Capital taking control in May 2024, the club reached the 2024-25 UEFA Champions League final (lost 5-0 to Paris Saint-Germain in Munich). Stars like Romelu Lukaku, Lautaro Martínez, Nicolò Barella and Marcus Thuram have defined the recent era. The Derby della Madonnina against AC Milan and the Derby d'Italia against Juventus are the country's most fervently contested fixtures.