I have bought a second hand copy of OCP’s “Guitar Accompaniment Book” on Abe Books. It is the 2005 edition but has some songs from the 2006 and 2007 supplement inserted into the loose leaf binder. It appears to be missing one or two songs but otherwise should fill in the songs from about 1996-2006 in the OCP canon that were too late for As One Voice 1&2 and not included in Spirit and Song 1&2. It also will fill some traditional hymn gaps.
This song is Owen Alstott’s translation of Puer natus in Bethlehem and the tune is obviously PUER NATUS. There are lots of slightly different translations of this text about so you might want to see the lyrics from the sample at OCP. The sheet music can be purchased there and you can hear a lengthy snippet of the chant version.
I’ve made two versions that are rhythmic because BIAB is lousy at free chant.
These are nice Latin versions: