Though we know that much has perished, the four Indexes of the 16th century give some idea of the rich repertory of the popular theatre, and of the efforts necessary to destroy it; moreover, the Spanish Index of 1559, by forbidding autos of Gil Vicente and other Portuguese authors, is interesting evidence of the extent to which they were appreciated in the neighbouring country.
In the West the works of Augustine are the great repertory for information on the subject of Manichaeism (Contra epistolam Manichaei, quam vocant fundamenti; Contra Faustum Manichaeum; Contra Fortunatum; Contra Adimantum; Contra Secundinum; De actis cum Felice Manichaeo; De genesi c. Manichaeos; De natura boni; De duabus animabus; De utilitate credendi; De moribus eccl.
As a work of art it can take but a low rank, but as a repertory of fragments and morsels of information it is invaluable.
There is a great deal of practical information on lenses in connexion with the camera and other optical instruments, and the book is valuable as a repertory of early practical optics, also for the numerous references to and extracts from previous writers.
And yet the book is an invaluable repertory of facts, and must endure until it is superseded by something better.
These books are valuable as a repertory of mythological stories.