This name is probably derived from that of an
ancient locality (a vicus?) near the church of S. Lorenzo in Panisperna
on the Viminal. The name comes into use about l000 A.D.; it was
previously, e.g. in Eins. I. II; 5.7; 7. 13, called S. Laurentii in Formoso or
ad Formosum, from the name of its founder (HCh 292-293; cf. HJ 376).