At Rome, the papal basilicas of St Peter and St Paul both lay outside the city walls: at Canterbury, Augustine founded an extramural burial church, dedicated to Sts Peter and Paul together.
2005, Julia M[ary] H[oward] Smith, “Rome and the Peoples of Europe”, in Europe after Rome: A New Cultural History 500–1000, Oxford University Press, section “Ideologies”, chapter section “Rome, ad 1027”, page 286