The first popular IDE was probably Borland's old Turbo Pascal for DOS. Turbo Pascal included an editor with a WordStar command set, a compiler for Pascal code, and an integrated debugger. If your code encountered a syntax editor while compiling, you were placed back in the editor, with the offending line of code highlighted.
GnuEmacs and XEmacs were originally just TextEditors , but because of their extensibility they got more and more IDE-like features. In addition they have got many additional extensions, that make them even more like IDE:
See the IDEFamily for a collection of IDEs