The Quill is a program to write home computer adventure games. Written by Graeme Yeandle, it was published on the ZX Spectrum by Gilsoft in December 1983. Although available to the general public, it was used by several games companies to create best-selling titles; over 450 commercially published titles for the ZX Spectrum were written using The Quill.
The Quill only allowed for the creation of text adventures (also called interactive fiction), using a text interpretation process known as a verb–noun parser. Later an add-on called The Illustrator was made to let the user include graphics in the adventures.
Source: Wikipedia, "[en.wikipedia.org/wiki/The_Quill_%28software%29 The Quill (software)]", available under the CC-BY-SA License.