Question: Who founded an American family notable for their social prominence, wealth, business enterprises and philanthropy, who has a member by marriage who isan American poet, writer, racehorse owner/breeder, socialite, and philanthropist ?  
Sentence (from "Whitney family"): The Whitney family is an American family notable for their social prominence, wealth, business enterprises and philanthropy, founded by John Whitney (1592–1673) who came from London, England to Watertown, Massachusetts in 1635.
Relevant evidence: Yes