Atrium

This is the ATRIUM,  w/ a fountain in the middle 
    Around the atruim is a roofed arcade
       This space was used as:
            a place for the congregation to gather 
            a place to to instruct converts 
            offices for church officials 

The atrium of a early Christian basilica seems to be 
     based on Roman domestic architecture country villas

(Here, we looked at a slide of the Atrium of the
    House of the Sliver Wedding  in Pompeii
     As you recall, the Roman town of Pompeii was
          buried by the eruption of Mt Vesuvius in AD 79 

Typical of the atrium of a Roman villa (or country house)
   there's the open part of the roof  surrounded by columns + 
      down on the floor is a pool for catching rainwater  

There's still discussion on exactly how the influences of the
     Roman basilica
     Imperial audience hall 
     Domestic architecture
           blended to form the early Christian basilica 
But it's easy to see that, given  the tradition of congregations 
  meeting in the homes of their wealthier members 
   --homes that probably had atria--
      could have been an influence in later church architecture