From 2002 to 2008 the biggest German games event was Games Convention, hosted by the Leipzig Trade Fair in the eastern German city that had been a centre of book publishing for centuries. For a brief period it was the largest games trade show in the world. But Leipzig was outgrowing its own infrastructure - too few hotel rooms, transport links that creaked under the volume of visitors. In 2008 the German games industry association, the BIU, announced it was moving the whole circus to Cologne starting in 2009. Leipzig refused to die quietly. The trade fair owners said they would keep running Games Convention on their own, without the industry body. For five months the two sides faced off, each claiming to be the authoritative German trade fair for video games. Leipzig blocked Cologne from using the name. Cologne went with GamesCom instead.

The two events were scheduled for the same weekend in August 2009. Two German cities. One industry. Game developers, publishers, and journalists had to choose. They chose Cologne. After a deal between Gamescom organisers and the Game Developers Conference, Leipzig folded - Games Convention was cancelled in physical form and replaced by an online-only show focused on mobile and casual gaming. That online event lasted exactly one year before being discontinued. The first physical Gamescom in August 2009 drew 245,000 visitors and 458 exhibitors, a number that has roughly doubled in the years since. The Federal Association of Interactive Entertainment Software continued to run it until 2018, when it merged with the industry body GAME. The show kept growing.

In 2019 Geoff Keighley - the Canadian games journalist who created The Game Awards - launched Opening Night Live, a streamed showcase the evening before the convention floor opens. Trailers premiere. Release dates leak. Studios time their biggest announcements to land on the ONL stage. It quickly became one of the most-watched events in the games industry calendar, the kind of presentation where a single trailer can drive a stock price. It has also drawn its share of weirdness. In August 2023, an attendee rushed the stage during Opening Night Live and interrupted Keighley, shouting that 'Bill Clinton wants to play GTA VI.' The same person had crashed The Game Awards 2022 eight months earlier and would interrupt several other live shows in Germany asking when Grand Theft Auto VI would arrive. Cologne has hosted both the announcements and the disruptions, the suits and the chaos.

When E3 - the Electronic Entertainment Expo, the legendary Los Angeles show that defined the games industry from 1995 to 2019 - was discontinued during the COVID-19 pandemic and never recovered, Gamescom became the largest event of its kind on Earth by default. It already was the largest by attendance; now there was no rival. In 2021 Gamescom Asia launched in Singapore, later relocating to Bangkok in partnership with Thailand Game Show. In 2024 Gamescom Latam debuted in Brazil and immediately became the largest gaming event in the Americas. The Cologne convention had grown from a local German show into a global brand - and along the way, the city of Cologne, which already had its cathedral and its carnival and its Eau de Cologne, added a slightly improbable new identity: capital of the gaming world for one week every August.