Surrexit Pastor Bonus (The Good Shepherd is Risen) is an Easter motet by Orlando diLasso (one of the great composers of the late Renaissance). The rising theme clearly indicates the mood of the work; the imitative counterpoint makes this a great piece for brass quintet.
The sheet music is published by the TBQ Press - http://www.tbqpress.com/ Scroll down their listings to find the piece.
It is lso available as an unpublished brass sextet.
The mp3 performance is from my CD “Savannah River Brassworks,” available on my Recordings page.