The Archbasilica of St John Lateran is the world's earliest cathedral. A Constantinian foundation pre-dating St Peter's in the Vatican, it remains the seat of the Bishop of Rome, the Pope, to this day. This volume brings together scholars of topography, archaeology, architecture, art history, geophysical survey and liturgy to illuminate this profoundly important building. It takes the story of the site from the early imperial period, when it was occupied by elite housing, through its use as a barracks for the emperor's horse guards to Constantine's revolutionary project and its development over 1300 years. Richly illustrated throughout, this innovative volume includes both broad historical analysis and accessible explanations of the cutting-edge technological approaches to the site that allow us to visualise its original appearance. '… this undoubtedly is the book to read to better understand the multifarious and intertwined material and ideological facets assumed by the Lateran over the centuries.' Yuri A. Marano, Medieval Archaeology The first inter-disciplinary study to examine the construction and development of the world's first cathedral from its origins to 1600. Lex Bosman is Professor of Architectural History at the University of Amsterdam, with a special interest in Early Christian and Medieval Architecture. He has been a fellow of the Royal Netherlands Institute in Rome and Scholar in Residence at the Istituto Universitario Olandese di Storia dell'Arte in Florence. He is the author of many publications, including The Power of Tradition: Spolia in the Architecture of St. Peter's in the Vatican (2004). Ian Haynes is Professor of Archaeology at Newcastle University, specialising in Roman Archaeology. He has directed twelve field projects in five countries and in 2019 was awarded an ERC Advanced Grant for a five-year investigation of SE Rome. He is the author or editor of eight books including Blood of the Provinces (2013). Paolo Liverani was Curator for Classical Antiquities at the Vatican Museum and is now Professor of Ancient Topography at the University of Florence. He is the author of eight books, including The Vatican Necropoleis (2010).