I was registered Mariana, which is the portuguese (and many other languages) version of Marianne or Marian. It's just Mary + Anne! Mariana can also be related to Mary, mother of Jesus - and all this religious thing.
It's soooo popular here in Brazil. I don't like it, 'cos there's nothing to do with my unique personality.
Anyway, every person seems to call me in crazy different ways they create, such as: Who (my bro), Flor (Flower in portuguese - my mom), Ani (my dad and a few friends), Marie, Mary, Maricota, Marizinha, Maribeau, Mary Poppins, Marijuana (no, I don't smoke pot!), Nana, Mary Crazy (no comments!), M. or the most common nickname for my name Mari. There are more, I can't even remember them all.
I wish my mom would have chosen Flor. It's pretty and can be easily pronouced in other languages.
At least, she dropped Camilla (her first choice) when I've apeeared to her for the first time.
Anyway, I prefer Mari, Ani or Marie.
I don't have a middle name. They'r not really common here in Brazil. Instead, we have our mother's maiden name as second last name.