Western music was, at least well into the 16th century essentially a modal music. This video from the youtube channel Early Music Sources gives an overview of how modes were undestood by Renaissance theorists.

The CERMAA, or CEntre de Recherches sur les Musiques Arabes et Apparentées is the research centre of the FOREDOFICO (FOundation for REsearch, DOcumentation and FIeld COllection for Oriental and Arabian Traditional and Folk Music and Arts). Through a website and an online journal (NEMO) the CERMAA published some interesting analyses regarding pitch and modes in extra-european musical traditions. (Link to the Youtube Channel here).

Louis-Albert Bourgault-Ducoudray seems to have been a nice fellow. Polite and sociable. Boundless energy. An insatiable musical appetite. And a solid commitment to world music. Brittany, Egypt, Greece, Cambodia, Ireland, Scotland... etc – he was willing to seek everywhere in his quest for resources to bring life back to Western classical music. A rejuvenation. A return to simplicity.

In this website Ed Emery presents the materials collected By Ducoudray in Greece between 1873 and 1878 representing the western, end of the XIX century point of view on "oriental" modal music.

link to the website here