SS Lazio is Rome's oldest surviving football club, founded on 9 January 1900 in the Prati district as Società Podistica Lazio, a multi-sport association established by nine young enthusiasts led by Luigi Bigiarelli. The name was drawn not from the city itself but from the wider Lazio region, reflecting ambitions that extended beyond Rome. The club's characteristic sky-blue-and-white colours, which gave rise to the nickname Biancocelesti, were inspired by the Greek flag, the birthplace of the Olympic Games, while the eagle on the club crest, a symbol of Zeus, was chosen personally by Bigiarelli.
A particularly important chapter in the club's history unfolded in 1927, when Italy's fascist authorities sought to merge all of Rome's football clubs into a single new entity, which ultimately became AS Roma. Lazio, largely thanks to the efforts of club official Giorgio Vaccaro, was the only major Roman side to resist the merger and preserve its independence and identity — a fact that remains central to the club's sense of self in relation to its local rival to this day.
At the domestic level, Lazio has claimed the Serie A title twice — in the 1973/74 season and in 1999/2000, when the league triumph was paired with victory in the Coppa Italia to complete a domestic double. The club's honours also include seven Coppa Italia trophies (the most recent in 2019) and five Supercoppa Italiana titles. The most fruitful period in the club's history came at the turn of the millennium, when, led by captain Alessandro Nesta, Lazio won the 1998/99 UEFA Cup Winners' Cup, defeating RCD Mallorca in the final, and, months later, as Italian champions, lifted the UEFA Super Cup after beating Manchester United.
Since the club's earliest days in football, Lazio has played its home matches at the Stadio Olimpico, shared with city rival AS Roma, and the two clubs' meetings — known as the Derby della Capitale — rank among Italian football's most emotionally charged fixtures. Despite financial difficulties in the early 2000s that forced the club to sell several of its star players, Lazio, under president Claudio Lotito, in charge since 2004, remains a regular presence in European competition and one of Italian football's most recognisable clubs.