What project codename did Microsoft use for Edge before naming it in 2015?

Microsoft used Project Spartan as the codename for Edge before announcing the browser’s final name in 2015.

Spartan was developed as a new Windows browser rather than simply another Internet Explorer release. Microsoft designed it to leave behind several older technologies associated with Internet Explorer, including ActiveX and legacy document modes. The project’s public identity changed when Microsoft revealed the Microsoft Edge name during its 2015 Windows 10 development period.

A common mix-up is Project Astoria, which referred to Microsoft’s Windows Bridge for Android apps, not the browser. Project Longhorn was an earlier codename for Windows Vista, while Gemini was used for other Microsoft projects. Spartan also should not be confused with the later Chromium-based Edge: the original Edge, now often called Edge Legacy, used Microsoft’s own EdgeHTML engine.