According to Nielsen (Nielsen 1945 I s. xxxv) parts of AM 782 4to and AM 784 4to are copied from the same exemplar and fols 80r-338r correspond to AM 782 4to, fols 1r-246r.
Nielsen: Middelalderens danske bønnebøger III 179-473 Var.app. 784.
Nielsen: Middelalderens danske bønnebøger IV 367-442 Fols 184r-186r, 265r-266r, 338v-339r, 341r-342v, 345v-346v.
Parchment.
194 mm x 133 mm x 70 mm. Contemporary brown blind-tooled calfskin over pasteboards on three sewing supports. The back cover is extended with a flap which is fastened to the front cover by to metal clasps. The outer spine has been renewed formerly. The clasps are decorated with the letters WAR on a cross-hatched background between a row of pearls surrounded by two straight lines.
The text on Árni Magnusson's slip reads: Ex auctione Rostgardianå |Num. 353. indicating that he aquired the manuscript at Frederik Rostgaard's auction in 1726.