Piacenza pilgrim, Antonini Placentini Itinerarium 19. See John Wilkinson, Jerusalem Pilgrims (Warminster, UK: Aris and Phillips, 1977), p. 83. For other pilgrim accounts that place Abraham’s altar on Calvary, see the discussion by Archer St. Clair, “The Iconography of the Great Berlin Pyxis,” Jahrbuch Berliner Museum 20 (1978), p. 23f.