The Third Astrological House - Goddess of the Moon
The Third House: Also known as the "Place of the Goddess of the Moon".  Paulus says this place is productive of possessions, usually ascribed to the 2nd house by modern astrologers, whereas according to most ancient sources, the 2nd indicates modes of making a living and whether one has success in acquiring property. Probably the reason this place is considered an indicator of possessions is because the Moon rejoices here and the Moon represents sustenance and material goods. One should also keep in mind that this blurring of meanings of the houses could be an indication of the flexibility of reality and a good reason not to take the trisections of the angles too rigidly. Other ancient sources say this place gives signs concerning brothers and being away from home. This is confirmed by the modern view that this place has to do with siblings, near relatives and with errands that have us moving around town.
There are other even more interesting observations. The opposite place (9th) has to do with orthodox religion, therefore this place has to do with unorthodox religion and beliefs on the fringe of society indicated by the "place of the Goddess". Modern astrology often compares the 3rd house to Gemini and to the mental variety that Gemini encourages. This is contrary to the orthodoxy of religion which Gemini's ideas constantly question. In the middle ages, the Moon became misunderstood by clerics to be aligned with darkness and evil, possibly because of it's association with the nocturnal sect. According to the church, a woman (the Moon) was responsible for bringing sin to Adam. Here, the Moon delights in contrareity, in Plato's "Other", seen by orthodox Christians of the past as contributing to heresy. So, this house gives signs for mental habits and early education/brain wiring (the mind), and alignment of faith.
Noting the natural contrareity of this place we gain new insight as to why it is that so many of us experience our siblings to be such a challenge while growing up. If we keep in mind the process that the houses map for our lives from birth to death, so far we have identity (1st house), attachment (2nd house) and now we have communication and learning and tolerance. Planets and lots placed here show the character of our communication, whether or not we face challenges in education, whether we stay near home or not or how we move around the neighborhood, our relationship to siblings and near relatives, etc...
More info on each of the planets that have dealings with this place: