Off-topic and will be closed here unless it connects to the desktop/laptop; instead consider [the site for Windows Phone](http://windowsphone.stackexchange.com). Mobile operating system, successor to the Windows Mobile platform.
Windows Phone is a mobile operating system developed by Microsoft as the successor to the Windows Mobile platform. It was officially unveiled on February 15, 2010 at the Mobile World Congress in Barcelona, Spain. The final SDK was released September 16, 2010.
The first version was Windows Phone 7, as seen below: