It was a reworked version of Spyglass Mosaic, which Microsoft licensed from Spyglass Inc., like many other companies initiating browser development.
The first version of Internet Explorer, (at that time named Microsoft Internet Explorer, later referred to as Internet Explorer 1) made its debut on August 24, 1995.
Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated IE or MSIE) is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. This is the version history of Internet Explorer.