John de Bohun was born about 1433 in Wales. He was the son of John de Bohun and Anne Halsham.
He married Avelina de Ros, daughter of Sir Robert Ros of Rockingham Castle, Northants. (Avelina was his step-sister.) Their first child was Sir Humphrey de Bohun (who married Margaret Estfield and had a son named John). John de Bohun III as a younger son had not inherited the family title, which goes to Wales sessein knight under one of the de Brasoe landholders. Sir John’s parents were Sir John de Bohun II and Anne Halsham.
Some sources sat that the Avelina De Ros who married John De Bohun was the daughter of Robert de Ros, 1st Baron de Ros (c. 1223 - May 13, 1285), was an English nobleman and the first holder of the ancient title Baron de Ros. If you do the math, it is not possible for him to have a daughter born almost 200 years after he died. There has to be more than one married into the Ros or Bohun lines.
In a book called Lists and Indexes, Issue 8, By Great Britain Public Record Office, 1897, I found a Robert de Ros of Ingmanthorpe. The date given is 5 November 1371. This is the date of his appointment or commencing account in Yorkshire. I am not entirely sure what that means, but listed on the same page is John, Constable of Halsham, knt. 26 November 1377. There is also another John Consatable of Halsham, Knt. 8 November 1436. Why are these men recorded under Yorkshire? Halsham was in West Sussex. These dates are also in the book, The Castle Community: the personnel of English and Welsh Castles, 1272-1422 by John Rickard.
Then I found out that a Sir Robert de Ros, Knt. Born 1265 in Helmsley,, North Riding, Yorkshire, England was married to Ernberge Constable, born 1283 Halsham, East Riding, England. They had a son named James who in turn had a son and grandson named Robert. It seems feasible to me that one of these Robert's may have been her father.
They had two sons:
1.Geoffrey Boone De Bohun born 1450 in Penmynydd, Anglesey, Wales and died 7 May 1472 Penmynydd, Anglesey, Wales and married Petrolina De Arderne.
2.Humphrey De Bohun, born 5 June 1418 of Midhurst died November 1468. He was Sheriff of Essex and married Margaret Estfield.