Italy, Rome, Old St. Peters, plan of west end showing
transept located between nave and apse (Jongkees, 1966)
The total length of St. Peter's from entrance to apse was about 123 m. (403 1/2 ft.); the nave alone was as long as an American football field (298 ft.). The combined width of nave and aisles was about 63.4 m. (208 ft.). The colonnades separating the five parallel spaces of nave and aisles had 22 columns each, for a total of 88 columns; there were also two columns at the end of each aisle (4 X 2 = 8) and two more at each end of the transept, to make the total of 100 columns for which St. Peter's was famous as we know from Gregory of Tours.
The nave elevation was like that of the Lateran cathedral, with a colonnade supporting a tall wall pierced by large windows; a similar elevation appeared between the aisles.