DURANDUS, Gulielmus (c.1237-1296, O.P., Bishop of Mende). Rationale divinorum officiorum, in Latin, ILLUMINATED MANUSCRIPT ON VELLUM [Italy, probably Bologna, first half of the 14th century]336 x 246mm. 133 leaves + ii (contents): 1-1310, 143(of 4, iv a cancelled blank) COMPLETE, catchwords in the lower margin of final versos, many signature marks survive in alphabetical sequence in red in the outer lower corner of the first half of each gathering (some trimmed), two columns of 51 lines written in dark brown ink in an as-glossing bookhand, some marginal corrections in another hand, justification: 232 x 72-15-70mm, rubrics in red, many of these with guide letters, paragraph marks alternately in red and blue, opens with a LARGE HISTORIATED INITIAL of Durandus, ground and marginal disks in burnished gold, six 6- to 20-line ILLUMINATED FOLIATE INITIALS painted in pink, green, blues and red, two large skeletal initials of red with blue flourishing, three-line initials throughout alternately in red and blue with flourishing of the other colour extending into margins, circular diagram of the lunar month in black and red ink (historiated initial rubbed, repair in the margin of the first leaf, a few leaves yellowed, light worming in first and last gatherings, occasional light soiling or small dampstain, margins of supplemental contents leaves repaired). 16th-century quarter-calf and wooden boards, calf panelled in blind with rolls and cornucopia tools, brass catches and clasps with leather straps (lacking spine, rubbed, boards detached and chipped, a few worm-holes). PROVENANCE: 1. The colophon records that Antonius of Bologna, friar of the Carmelite Order, wrote the manuscript for Richard of England, doctor of theology. 2. Title inscription in a 17th-century hand on opening folio signed 'R' 3. Springfield Library, Mass. gift of Mrs. Dorcas Chapin, July 1887 (bookplate and manuscript shelf-mark). De Ricci, I, 1066. CONTENT: Durandus was one of the principal canonists of his day. He taught at Modena, and possibly Bologna where he had studied. Soon after being appointed Bishop of Mende in 1285, Durandus began writing his Rationale (1286-1291). This compendium on the mystical origins and meaning of the liturgies is his most influential work. The Rationale became one of the most popular manuals of Christian worship in the later Middle Ages. It circulated widely in manuscript, its popularity cemented at the dawn of printing when, in 1459, it became only the fourth book ever printed. Durandus's arrangement of pontifical ceremonies is the direct ancestor of the Clementine Pontificale Romanum which was in use until recent times. ABPC records only one leaf from this text having sold at auction in over 30 years.