The Crystal Cathedral

6. A church under which are ranged metropolitical churches and their provinces is a "primatial cathedral".
7. A church to which primatial, metropolitical, and cathedral churches alike owe allegiance is a "patriarchal cathedral".
The removal of a bishop's cathedra from a church deprives that church of its cathedral dignity, although often the name is retained in popular use, as for example at Antwerp, which was deprived of its bishop at the French Revolution as well as former cathedrals acquired by the Presbyterian Church of Scotland (which lacks episcopal structure). Technically, such churches are proto-cathedrals.
The title of "primate" was occasionally conferred on metropolitan bishops of sees of great dignity or importance, such as Canterbury, York and Rouen, whose cathedral churches remained simply metropolitical.