Fourth Sunday after Trinity Mass Chant Propers

 Mass Proper Chants for Fourth Sunday after Trinity via google drive.  

Example from the Introit:

Mass Proper Chants for 13th Sunday after Trinity

 

Mass Proper Chants for the Thirteenth Sunday after Trinity, via pdf files on Google Drive:

Introit

Gradual

Alleluia

Offertory [with verses]

Communion [with Psalm verse]

Gregorian Chant in Old High German

 

An example from the late 9th or early 10th century, where they actually began to put Old High German to Gregorian Chant. While not the same as a full blown Old High German Divine Office or Mass, it does show you that this was not so closed a question as many of us [myself included] had originally thought:

https://www.youtube.com/watch?v=Of6uBetvjB4