This is another very useful video of the project Early Music Sources. This episode is dedicated to the modal theory in the sixteenth and seventeenth centuries. This is not so simple as may be suggested in the video but, still, it is an excellent resource to understand it.
Treatises mentioned range from Glareanus’s Dodecachordon to Zarlino and Adriano Banchieri. There are also clear graphic examples between the 8-mode theories and 12-mode theories which can be very useful.
As in previous episodes, a page of footnotes is provided in the project websites.