The author here examines the memoriae, the monuments in memory, of the apostolic princes Peter and Paul as they are found in Rome in archaeological monuments and in literary tradition. In this connection various archaeological excavation reports are presented and critically analyzed. At the center lie the excavations under S. Sebastiano which have proceeded since 1915, and those under S. Pietro since 1939, which have been of worldwide interest yet at the same time have left many unclarities.