This important collection of tales draws upon pre-Christian Celtic mythology, historical accounts and international folk tale motifs - the product of a highly-developed mediaeval Welsh narrative tradition, both oral and written.
Books can be attributed to "Unknown" when the author or editor (as applicable) is not known and cannot be discovered. If at all possible, list at least one actual author or editor for a book instead of using "Unknown".
Books whose authorship is purposefully withheld should be attributed instead to Anonymous.