Although this document has been considered by some as a licence to crenellate the current opinion rejects this as a licence to crenellate.
In 1195 Hugh de Say was licensed by Richard I to refortify the castle. This reported licence seems actually to be a royal grant of money (five pounds) to repair the castle. Not, in a meaningful sense, a licence to crenellate although has been called this by some.
Significant later source are;
Hugh de Say (b c. 1156-1197) of Richard's Castle, Herefordshire, England. He married Mabel Marmion c. 1180, daughter of Robert Marmion and Maud de Beauchamp. He was Keeper of Norton Castle (in Radnor), and fought under Richard I in Normandy in 1194. In 1196, he and Roger de Mortimer of Wigmore were defeated near Radnor by the Welsh prince Rhys. He appears to have been living in early 1197, but died s.p.m. before Michaelmas of that year. His widow, Mabel, was remarried by Easter 1201 to one Reynold, whose identity is not further known, and she was deceased before Michaelmas 1210. (CP: Vol VI[453], Vol IX[255-258]; AR: Line 177[2-3].)
Biographical source include;
More details about licences to crenellate can be found here.
Please let me know if you see any errors, can add information or can otherwise help to improve this resource. Contact me