“The Minstrels of that noble house all clad in robes of blue, with silver crescents on their arms attend in order due. Then journeying to the Holy Land, there bravely fought and died, but first the silver crescent won some paynim soldans pride”.
The image on the right is seen in a private garden in Alnwick and would have once adorned the parapet of Alnwick Castle. This chap says he is a Turkish Sultan and he has 3 crescent moons on his shield.
I think it is an effigy of the warrior William de Percy conquered in the Holy land C 1097.