The fame of the New
York socialite and philanthropist
Brooke Astor (born
Roberta Brooke Russell) is probably what originally turned this formerly masculine name into a popular name for girls. Indeed, 1953, the year she married
Vincent Astor and first received publicity, was also the first year
Brooke appeared on the SSA top 1000 list in the USA.
http://www.nndb.com/people/173/000057002/