King John's bastard son, Richard Fitz Roy, was known under several designations as follows:.
Cal. of Liberate Rolls 2 (1930): 136 (Richard de Chilham styled
"king';s brother"). Curia Regis Rolls 16 (1979): 115,145,169,178
(instances of being styled "Ricardus de Chilham"), 175 (styled
"Ricardus Fiz le Roy"), 232 (styled "Ricardus de Warenn' filius regis
Johannis"), 450 (styled "Ricardus de Warein'"); 17 (1991): 26 (styled
"Ricardus filius Regis de Chileham").
One of Richard's seals which has survived calls him Richard de
Warenne. Due to his various forms, I have elected to call him Richard
Fitz Roy (otherwise de Warenne, also de Chilham) in the forthcoming
book, Plantagenet Ancestry.
Interestingly, Richard's son, Richard the younger, was known as both
"de Dover" and "de Chilham" as appears below:
Cal. of Liberate Rolls 2 (1930): 122 (Richard son of Richard de
Chilham styled "king's nephew"), 249 (Richard de Dovor styled "king's
kinsman").
As for Philip Fitz Roy, if you know of a original contemporary record
which specifically refers to Philip as "Philip de Cognac," please let
me know. Kindly provide your source.
Best always, Douglas Richardson, Salt Lake City, Utah