In Greek and Roman architecture a peristyle is a columned porch or open colonnade in a building that surrounds a court that may contain an internal garden. "Tetrastoon" (Greek: "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.
In rural settings a wealthy Roman could surround a villa with terraced gardens; within the city Romans created their gardens inside the domus. The peristylium was an open courtyard within the house; the columns or square pillars surrounding the garden supported a shady roofed portico whose inner walls were often embellished with elaborate wall paintings of landscapes and trompe-l'oeil architecture. Sometimes the lararium, a shrine for the Lares, the gods of the household, was located in this portico, or it might be found in the atrium. The courtyard might contain flowers and shrubs, fountains, benches, sculptures and even fish ponds.