I believe that I've mentioned before that Robin came to me whilst folding laundry. I had Fairy Godmothers on my mind, and rebellious princesses ... and I had a random thought.
What if a girl received the wrong gift from her Fairy Godmother? What if she was given the gift of Best Swordsman in the World.
Instantly, I was creating a backstory for her. Hmm ... how could the gift been messed up? At the time, she was going to be a peasant, so I had the brilliant idea of, what if her father, the day she was born, was telling people in the village tavern or something that his wife had given him a son (hadn't occurred to him that it might be a daughter) and a passing fairy overhears and decides that she will gift this man's first son with an amazing gift, so hurries to his house and before the wife can say that it's a girl, gives the child the gift of best Swordsman in the World. (This was partially inspired by Milo and Otis, a movie about a cat and a dog. I've never seen the beginning, but I've seen the ending several times)
Of course, once the mistake is discovered, the fairy is gone and nothing can be done. I decided that the child should be named Robin and that she would be raised as a boy until she learns that she's really a girl at which time she decides to go find the Fairy Godmother and get things set straight.
Now that I had this wonderful character, I needed a story for her. Then I had a brilliant idea! What if I stuck her in that Sleeping Beauty sequel that I was trying to write (and which was going nowhere fast)?
I had the scene perfected in my head. Sleeping Beauty would be walking along one day, and suddenly be attacked by a band of thieves. A young lad would jump out of the woods, fend off those thieves with a swing of his sword and some fancy footwork ... and then turn around, take off his helmet ... and long, straight brown hair would tumble down.
Yup, straight brown hair. My original picture had her with straight hair.
I don't remember when Robert came along, but I do know that he was originally going to be younger by 2-4 years, and that his original name was ... Rednal. I blame the Unicorns of Balinor for that stunt.
And then I decided to tell my idea to my mother ... who changed everything, from their rank, (making them prince and princess) to the fact that they were twins, to Robert's name. (The reason I held back on naming him Robert was the fact that I had another character named that, who was also a twin. Oh, and a cousin or three named Robert)
I finally had a break-though on my Sleeping Beauty book, but then I encountered writer's block again. I was going too fast, and the character whose POV I was using knew too much, (my policy in choosing a main is the one who knows the least and is in the most scenes. That way explaining things isn't awkward and the readers don't feel like the character is withholding knowledge from them)
So I awarded POV to Robin, and in places, Robert, and the story simply spun out of my fingers. (Helped that I chose that month to do NaNoWriMo for the first time.)