When a Rockefeller turns 21 he or she publicly introduces him or herself to the wider Rockefeller clan at one of the bi-annual family gatherings – in June at the Playhouse on the grounds of the historic family estate in New York’s Hudson Valley or in New York City over Christmas. “They tell a little about themselves and people ­welcome them,” Peter Johnson, a longtime family consigliere says. “The idea is to say you are part of the family.”