Blackletter, also known as Gothic script or Gothic minuscule, was a script (or family of scripts) of the Latin alphabet used throughout Western Europe from approximately 1150 to 1500. It continued to be used for the German language until the twentieth century.
Blackletter is sometimes called Old English, but it is not to be confused with the Old English language, despite the popular, though mistaken, belief that it was written with Blackletter.
The Old English (or Anglo-Saxon) language pre-dates Blackletter by many centuries, and was itself written in the insular script. Read more about blackletter fonts on Wikipedia.