On the marriage of Josceline with Agnes, he took by express stipulation the name of Percy, that he might preserve the name of the house; and he quartered his arms with were or, a lion rampant azure, with hers, which were azure five fusils in fess or.

From Historical Anecdotes of Heraldry and Chivalry, by Susannah Dawson Dobson, p110

Some people assign the origin of fusils being borne in arms to the Crusades, and that they were given to their bearers as a mark of infamy for cowardice. I think, however, there were other reasons. […] Perhaps they were given as the symbols of industry and application.

From Historical Anecdotes of Chivalry and Heraldry by Susannah Dawson Dobson, p100-101