It wasn't for tax purposes, but for privacy and tranquility that the airy old manses on Tradd or Legare turned their shoulders to the world.
I didn't enter one of these homes, but I can imagine the cool breezes that would flow from the portico ceiling fans. There would be rocking chairs, of course, and tall glasses of iced tea, beaded with moisture.
To enter you'd step through a portal that led from street to porch. A false door? Perhaps, but it provided an extra layer of protection between inside and out.