Description of the Inner Court, the Arcades and Porches
In the next place he enclosed the atrium which occupied the space leading to the entrances in front of the church. This comprehended, first the court, then the porticos on each side, and lastly the gates of the court. After these, in the midst of the open market-place, the general entrance-gates, which were of exquisite workmanship, afforded to passers-by on the outside a view of the interior which could not fail to inspire astonishment.
Source: Life of Constantine (New Advent)