Ralph de Diceto

Opening page from the St Alban's Abbey copy of Ralph's Abbreviationes Chronicorum and Ymagines Historiarum, featuring a table of the innovative marginal signs he introduced to help index his work

Ralph de Diceto or Ralph of Diss (Latin: Radulfus de Diceto; c. 1120 – c. 1202) was archdeacon of Middlesex, dean of St Paul's Cathedral (from c. 1180), and the author of a major chronicle divided into two parts—often treated as separate works—the Abbreviationes Chronicorum (Latin for "Abbreviations of Chronicles") from the birth of Jesus to the 1140s and the Imagines or Ymagines Historiarum ("Images of Histories") from that point until 1202.