This "Peanuts" character got a sister named Sally in 1959
.... 
SALLY -- FIRST APPEARANCE: August 23, 1959 - Charlie Brown's little sister .... 
Charles "Charlie" Brown (occasionally called Chuck by certain characters) is the 
main... [DOC] [TLE] Amazon.com: Customer Reviews: The Complete Peanuts 1959 ... [PAR] Charles Schulz had established his main characters (Charlie Brown, Snoopy, 
Lucy, .... His new baby sister's name is Sally.