The Third House of the Horoscope is naturally ruled by Gemini and, as such, the planet Mercury. Known as the house of communication this part of the horoscope shows how we express ourselves and with whom. As with the first two in the chart, this is a personal house, very much about one’s self-expression and the connection with those in their immediate environment. Here, intellect also comes into play since our thinking processes are reflected by our communication style. The sign on the cusp, as well as any planets that reside here, suggests one’s style and preferences for communication as well as the thinking processes that underlies our actions.