Given a sentence and two mentions from the text (arguments), indicate a phrase (a verb or noun phrase) that describes the relationship between the provided arguments.

Sentence: 'She wrote Captain James West was the youngest son of John West of Thame , Oxfordshire and grandson of John West , who married twice , first a sister of his cousin Lord De La Warr , second a daughter of Sir James Lambert Bt . who had issue .', Argument/Subject 1: 'jame', Argument/Subject 2: 'john'
be son of