Reminded of "Crux Fidelis" by my selection on Thursday, here's the first melody that springs to mind whenever someone mentions those words. (And the playlist thus far.)
Crux fidelis, inter omnes
arbor una nobilis:
nulla silva talem profert,
fronde, flore, germine.
Dulce lignum, dulces clavos,
dulce pondus sustinet.
Faithful cross, above all other,
One and only noble tree:
None in foliage, none in blossom,
None in fruit thy peer may be.
Sweetest wood and sweetest iron,
Sweetest weight is hung on thee!
Attribution(s): "Glockenspiel Bells" by cocoparisienne (via the Visualhunt site).