The document which forms the subject of this article is from the collection of papyri in the Brooklyn Museum, New York. It is published here by kind permission of the Museum authorities in advance of its appearance as no. 24 in the Catalogue of Brooklyn Museum Papyri, which is being prepared by Dr. John Shelton. We are very grateful to Dr. Shelton for drawing our attention to this papyrus and for generously allowing us, because of its exceptional importance, to publish it separately in this article.The papyrus contains a Latin document relating to a unit of the Roman army stationed in Egypt. It is written in three columns on the recto of a piece of papyrus measuring approximately 27 × 18 cm. The verso, which according to Dr. Shelton contains a Greek private letter, has no apparent connection. Although the papyrus shows damage on all four sides, it is probable that the right-hand edge is preserved in lines 12 f. of the third column (see the notes ad loc). As it can be demonstrated that not much is lost at the left of the first column, what survives is likely to be the greater part of the original width. All three columns are incomplete at both top and bottom, and the loss here is much harder to estimate. Format and date are discussed in detail in section iv. It is here sufficient to say that it belongs in or near the year A.D. 215, and that in content it closely resembles two known papyri classed as pridiana, which have recently been re-edited as RMR 63 and 64.