The publication of this Corpus Inscriptionum et Monumentorum Religionis M ithriacae is due mainly to the activities of the Koninklijke Vlaamse Academie van Wetenschappen, Kunsten en Schone Letteren (The Royal Flemish Academy of Arts and Sciences) at Brussels, for this work was begun as an entry in a compe- tition organized by their Department of Fine Arts and Literature. It was then awarded a prize by a committee elected by the Academy and consisting of the theologian Prof. J. Coppens, the orientalist Prof. G. Rijckmans and the archaeolo- gist, the late Prof. H. van de Weerd. Among the first who should be mentioned with respect and gratitude is my teacher Dr. F. J. de Waele, Professor in Archaeology and Ancient History at the Nijmegen University and member of the Royal Flemish Academy. This remarkable teacher inspired a deep interest in the study of Archaeology and of the Mithras cult, and his help has always been invaluable. I am also greatly indebted to the renowned Belgian scholar Prof. Franz Cumont. He was among the first to recognize the necessity of a revision of his standard work Textes et Monuments relatifs aux Mysteres de Mithra. During the last few years before his de'ath he showed a lively interest in the present study, supplied much material and often gave advice, devoting a great part of his leisure and his love of Classical Culture to this new publication of the Mithraic Monuments.