So When Exactly?
The Xbox 360 console was originally conceived as early as 2003, and the platform went through many various prototype names (including Xbox Next, Xbox 2, Xbox FS or NextBox), before, in February 2003, the final development title of 'Xenon' was settled upon.
Planning for the software platform began in earnest, with Microsoft's Vice President, J Allard heading proceedings. Later that month, an event was held in Bellevue, Washington for 400 developers, to try to recruit support for the fledgling system, and in the same month, Peter Moore, former president of Sega of America, joined Microsoft.
On August 12, 2003, ATI signed on to produce the graphic processing unit for the new console, a deal which was publicly announced two days later.
When Was The 360 Announced?
The Xbox 360 was officially announced on May 12th, 2005 on MTV in a program called 'MTV Presents: The Next Generation Xbox Revealed'. This was a special hosted by Lord of the Rings star Elijah Wood and featured a musical performance by The Killers. The Xbox 360 was also featured on the cover of TIME Magazine's May 23, 2005 issue with an article written by Lev Grossman.
Microsoft chose a November 2005 release date not because they wanted to be first to market like many originally thought, but because they thought Sony would ship their PlayStation 3 at that point. The system, along with some playable games, was shown off at E3 2005.
So What's Next For The Xbox?
So there you have it, the Xbox 360 was 'invented' way back in 2003, before finally being released to the public in 2005. It has survived a long six year lifespan, which is a lot longer than many consoles have lasted before. It is expected that a successor to the Xbox 360 will be announced at 2012's E3 conference, with a possible release date as early as the holiday season of 2013.
