The numberless romances that sprang up in the literary period of
the Middle Ages may be thrown into three groups:

1. Those belonging to the legend of Arthur and the Round Table.
They had their starting point in the history of Geoffrey of
Monmouth, which was partly invented, but had some basis in a
tradition common to the Bretons and the Welsh. The romances based
upon this legend sprang up apparently simultaneously in England
and France. Through minstrel romances, founded upon the Breton
popular tradition, the Arthur legend probably first found its way
into European literature. With it was early fused the stories of
the Holy Grail and of Parzival. In the twelfth century these
stories were widely popular in literary form in France and
Germany, and later they passed into Italy, Spain, and
Scandinavia. Their influence upon the life and thought of
Mediaeval Europe is very important. They did much to modify the
entire institution of chivalry.[1]

[1] Leon Gautier's "Chivalry", chap. IV., Section V.


2. The Romances of Antiquity, of which there are three varieties:

(1) Those which were believed to be direct reproductions, such as
the Romances of Thebes, of Aeneas, of Troy, whose authors
acknowledged a debt to Vergil, Statius, and other classic
writers.

(2) Those based upon ancient history not previously versified,
such as the Romance of Alexander.