See the twelve references to the word 'virgada' in the index of the Cartulary.
It is also mentioned in the Cartulary of the Holy Sepulchre in the year 1177.
The cartulary mentions his name at various intervals from 1197 to 1202.
A Latin text of this prophecy is to be found on the fly-leaf of the Cartulary of Thérouanne.
The last clause is clearly an addition by the cartulary ...