Could this be "Non nobis, Domine?" Old hymn; appears in the post-Agincourt scene in Branagh's Henry V, scored by Paddy Doyle.

Non nobis, Domine, Domine
Non nobis, Domine
Sed nomine, sed nomine
Tuum da gloria?

(Not to us, o Lord, not to us, but to Your name give the glory.)

The Latin is very old -- Shakespeare's 1599 text has Henry saying that for the victory they should sing "Non nobis" and "Te Deum."