James Berkeley, of Thornbury

See Peter Bartrum, https://cadair.aber.ac.uk/dspace/bitstream/handle/2160/6400/PERROT%... (August 18, 2017; Anne Brannen, curator)

Many sites show James as a son of both Maurice and his wife Isabel:

https://en.wikipedia.org/wiki/Maurice_Berkeley,_3rd_Baron_Berkeley

https://www.findagrave.com/memorial/67514872/isabel-berkeley:

Isabel was the daughter of London merchant Philip Meade and his wife, Isabel.

She married Maurice de Berkeley, the second son of Sir James Berkeley and his third wife, Isabel Mowbray. They married in 1465 and had three sons and one daughter: Sir Maurice Lord Berkeley, Sir Thomas Lord Berkeley, James and Anne, wife of William Denys.

https://www.werelate.org/wiki/Family:Maurice_De_Berkley_and_Isabel_Mead_(1)

http://www.tudorplace.com.ar/BERKELEY1.htm#James%20BERKELEY2

http://homepages.rootsweb.com/~tmetrvlr/berkeleya.html