Pivot of the Sun's Rising (Tuba Euphonium Quartet)

This new work for tuba/euphonium quartet is a fugue based on the Gregorian Chant "A Solis Ortus Cardine".

The Latin text is:

A solis ortus cardine
Ad usque terrae limitem
Christum canamus Principem
Natum Maria Virgine.

The nineteenth century translation by John Mason Neale is:

From the pivot of the sun's rising
To the farthest edge of the earth
Let us sing to Christ our Lord
Born of the virgin Mary.

I purposely crossed voices a bit to accommodate the members of the quartet.

Such serious instrument combinations are very difficult to pull off. The overall sound is very nice but there are moments where, in my opinion, the lower parts conflict, especially when they move into faster notes in those deep registers, and do not do so in parallel.
I really like that you looked to Gregorian chant for inspiration.