A long-standing objective for the Lateran Project has been to draw on structural evidence from the Lateran scavi to model the Constantinian Basilica.Lex Bosman has similarly sought to model the structure, initially from observation of the fabric of the standing Archbasilica. This chapter presents the happy outcome of collaboration between these two approaches.Using state-of-the-art visualisation techniques, the authors have brought together the evidence for the interior and exterior appearance of the Constantinian Basilica. The chapter argues that while based on exhaustive research, these 3D models should nevertheless be best understood as ߢprovocationsߣ.Production of these ߢprovocationsߣ is itself an important vehicle for analysis, because it exposes gaps in understanding as each new model drives and is driven by evolving debates about structure, decoration and illumination.

This paper concentrates on the representation of the Constantinian Basilica in the Liber pontificalis and determines its role in the text and in the representation of the pope.The sections considered range from the foundation of the Basilica in Life 34 (Pope Silvester I) to the significance of the Basilica for Pope Stephen V in Life 112.One oddity about the Liber pontificalis is that it never refers to the Constantinian basilica as dedicated to St John. That information is supplied in liturgical books such as the Sacramentaries and Lectionaries extant in Frankish manuscripts. This prompts a reflection on the Constantinian Basilicaߣs liturgical role within Rome that casts further light on the possible implications and peculiarities of the Basilicaߣs representation in the Liber ponificalis itself.

The reconstruction of the Constantinian Basilica at the Lateran by Krautheimer and others leaves several important questions unresolved. A combination of evidence corroborates the reconstruction by Krautheimer of the two rows of nave columns of red granite. Two yellow marble columns which since the end of the sixteenth century support the organ tribune however are never mentioned in relation to the reconstruction of the fourth-century church-basilica. In fact they can be traced back to their medieval presence in the portico on the east side of the building. Their similarities with the equally yellow marble columns on the Arch of Constantine support the notion that they belong to the original, early fourth-century structure of the Basilica Constantiniana. The obvious question where they may have been positioned in the Early Christian basilica can be answered by using the archaeological evidence under the basilica. Part of a foundation running west-east underneath the south transept offers a very likely foundation for a colonnade of two yellow columns on both the north and the south side as a continuation of the rows of green marble columns between the inner and the outer aisles.