Leslie Brubaker is Professor of Byzantine Art and Director of the Graduate School (College of Arts and Law) at the University of Birmingham. Her previous publications include Vision and Meaning in Ninth-Century Byzantium: Image as Exegesis in the Homilies of Gregory of Nazianzus (1999) and, with John Haldon, Byzantium in the Era of Iconoclasm: The Sources (2001). She has edited Byzantium in the Ninth Century: Dead or Alive? (1998) and co-edited, with Robert Osterhout, The Sacred Image East and West (1995) and, with Julia M. H. Smith, Gender in the Early Medieval World: East and West, 300-900 (2004). John Haldon is Professor of History and Hellenic Studies at Princeton University and is currently a Senior Research Fellow at the Dumbarton Oaks Center for Byzantine Studies. His previous publications include Byzantium in the Seventh Century: The Transformation of a Culture (1990; revised edition 1997) and Byzantium: A History (2000). He has edited The Social History of Byzantium: Problems and Perspectives (2008) and co-edited, with Elizabeth Jeffreys and Robin Cormack, The Oxford Handbook of Byzantine Studies (2008).