Help identifying very old sheet music

by anon-1080

Throwaway account for anonymity in case this turns out to be a major find.

I found this cool document. It's obviously sheet music, written on sheepskin or something similar, but can anyone help me identify the notation(some form of mensural, I think?) and an English translation of the text (some variant of latin?), as well as a best-guess as to the time and region of its origin?

https://imgur.com/a/TDAg6l8

Side note: It's not so squiggly in real life - from the front it's very even. I took it from a very steep angle to avoid a glare, and then edited it back to a rectangle.

Thanks in advance!

Platypuskeeper

Yes it looks like vellum, although the resolution is too low to say for sure. But it would be expected to be on that as well, given the skill of the calligraphy and fancy initial 'T'. Probably a leaf from an antiphonary. It's in Latin and consists of Psalm 118 (119):4-5 from the Latin Vulgate:

Tu mandasti mandata tua custodire nimis.

Utinam dirigantur viæ meæ ad custodiendas justificati[ones tuas].

(omitting the "Cör." in red at the start which I think is direction) In translation (New International Version)

You have laid down precepts that are to be fully obeyed.

Oh, that my ways were steadfast in obeying your decrees!

In terms of calligraphy and style it it has some older style elements but doesn't quite look medieval. It's very similar to the manuscripts here that are Spanish and from around 1600 (both in style and content);particularly this. The 'a' in particular ('Gloria' above the initial) is very distinctive; sort of mixing the diamond shape from Blackletter but lots of rounded Uncial/Humanist-like bits everywhere else. If such an 'a' was in use in the Middle Ages, I've not seen it and it's not in Bischoff's Latin Palaeography.