Most things I’ve read about Dogues point to them as having descended from Mastiff breeds, and I’ve heard of it being referred to as a French Mastiff. In fact, most dog encyclopedias I’ve seen have them double-indexed under DDB and FM.
Just as Dogue means mastiff in French, dogge also means mastiff in German.
Therefore my Great Dane, is not actually danish, as the germans call them the Deutsche Dogge, or german mastiff.
The Great Dane was developed from English Mastiffs and greyhounds, while the DDB was probably developed from the English Mastiff and various bulldog breeds. Just my wag.