art 1: Experiencing sacred thresholds. On the threshhold: Paul the Silentiary's Ekphrasis of Hagia Sophia / Emilie M. van Opstall -- Entering the baptistry: Spatial, identity and salvific transitions in fourth- and fifth-century baptismal liturgies / Juliette Day -- From taboo to icon: The entrance to and the exit from the church in the first three Greek liturgical commentaries (ca. 500-730 CE) / Christian Boudignon -- Bonus intra, melior exit!: 'Inside' and 'outside' at Greek incubation sanctuaries / Ildikó Csepregi. Part 2: Symbolism and allegory of sanctuary doors. Sanctuary doors, vestibules and Adyta in the works of neoplatonic philosophers / Lucia M. Tissi -- The paradise of St. Peters / Sible L. de Blaauw -- Imagining the entrance to the afterlife: Peter as the gatekeeper of heaven in early Christianity / Roald Dijkstra. Part 3: Messages in stone. The Queen of Inscriptions contextualized: The presence of civic inscriptions in the pronaos of ancient temples in Hellenistic and Roman Asia Minor (fourth century BCE-second century CE) / Evelien J.J. Roels -- Versus De Limine and In Limine: Displaying Greek paideia at the entrance of early Christian churches / Gianfranco Agosti -- The door to the sanctuary from Paulinis of Nola to Gregory of Tours / Enduring characteristics and evolutions from the Theodosian to the Merovingian period / Gaëlle Herbert de la Portbarré-Viard. Part 4: The Presence of the Divine. Filters of lights: Greek temple doors as portals of epiphany / Christina G. Williamson -- The other door to the santuary: The apse and divine entry in the early Byzantine church / Brooke Shilling.