Executive Director, Medieval Studies Program, PhD, University of Toronto. Historian of the society and culture of Medieval and Early Renaissance Siena and Tuscany.

• The Magnates of Siena, 1240-1420. 2 vols
• Medieval and Early Renaissance Italy
• Manuscript Studies I: Paleography
• Manuscript Studies II: Diplomatics and Codicology
• Sexual and Economic Ethics in Medieval and Early Renaissance Italy

• Culture and Society of Medieval Seina
• Coedited The Blackwell Companion to the Middle Ages

• Enterprise and Liability in Sienese Banking, 1230-1350.
  Medieval Academy of America, 1988
• Encyclopedia of the Medieval World. 2 vols.
  Facts-On-File, 2005
• Coedited with Mark Meyerson: Christians, Muslims and Jews in Medieval and Early Modern Spain.
  University of Notre Dame Press, 1999.
• Blackwell Companion to the Middle Ages
  Blackwell, May 2009
• Edited: Mediaeval Studies, 1988-1990.

• Manuscript Studies I, 2009, 2012, 2014, 2015
  Latin Paleography
• Manuscript Studies II, Spring 2009, 2012, 2012, 2015
  Diplomatics/Codicology
• Medieval Latin (Fall 2008, 2010, 2012, 2014

• Lila Wallace/Readers Digest Visiting Professor, Harvard’s Villa I Tatti in Florence
  January to June 2008