I made a couple changes based on the lyrics in the Chieftains' Long Black Veil Songbook:

Grief and pain are all I know
my heart is sore my tears aflow
we saw him go our buachaill beo
no word we know of him och on

A proud and gallant chevalier
a high born scion of gentle mien
a fiery blade engaged to lead
he'd break the bravest in the field

Then we'll sing his praise as sweet harps play
and proudly toast his noble frame
with spirit and with mind aflame
so wish him strength and length of day