Peristyle

In Hellenistic Greek and Roman architecture a peristyle is a columned porch or open colonnade in a building surrounding a court that may contain an internal garden. Tetrastoon (pronounced /tetrastohon/, from Greek τετράστῳον, "four arcades") is another name for this feature. In the Christian ecclesiastical architecture that developed from Roman precedents, a basilica, such as Old St Peter's in Rome, would stand behind a peristyle forecourt that sheltered it from the street. In time the cloister developed from the peristyle.