Today, the third day of the third month, is Hina Matsuri in Japan. Doing a little research online for myself this morning, I found several bits of information that I didn't know about the festival before.
1. The festival originally came from China.
2. The dolls were first made of paper, rubbed over the body in order to absorb impurities, and then cast into a body of water or burned.
Here is a site with good information on dolls. I'd never made the connections between all the dolls. Pretty interesting.