In antiquity the term “basilica” denoted a rectangular hall, usually divided by pillars and used for various purposes. From the fifth century a.d. its main use was for churches. When official permission was given to build churches under Constantine (306–37), this form was commonly chosen, adopted from secular, rather than pagan, sacral architecture. If the details were borrowed from Roman places of assembly, the structure as a whole was something new: a rectangular building, divided by colonnades into a broader and …