Literary treasure and cultural soothsayer Toni Morrison wrote, “A sister can be seen as someone who is both ourselves and very much not ourselves—a special kind of double.” National Sisters Day, celebrated on the first Sunday in August recognizes that special double and the bond between sisters both born and found. From the rivalry between Queen Elizabeth I and her sister Mary Queen of Scots to the modern warfare among the Kardashian-Jenner clan, sister dynamics offer a wealth of intrigue. A source of strength, joy, envy and ire since we as humans first consciously shared a cave floor, the bond of sisters extends not just to blood relatives but to female friendships that feel like family. How we love is informed by myriad circumstances and astrology can help us understand both our love languages and our relationship failings. With this in mind I bring you a list of the star signs as sisters alongside celebrity siblings that serve as examples for how sister love manifests across the zodiac wheel.