(Latin: regerere, to inscribe)
The copies, generally entered by the papal chancery in special registry volumes, of papal correspondence and official documents, both ancient and modern.
This custom probably antedates Constantine, and can be positively proved for the 4th century and onwards, althovgh nearly all the copies up to the end of the 12th century have disappeared.
The earlier books of record were called also commentarii, and the archive in which they were kept, commentarium.
Both paper and parchment were used.
The most important fragments of the various periods: are: about 850 letters of the regesta of Gregory I (590-604); some letters of John VIII (872-882), 55 of which are in the British Museum, together with correspondence of six other popes; about 70 letters from the regesta of Adrian IV (1154-1159) and several others, at Cambridge; 381 letters of Gregory VII (1073-1085), constituting, however, merely an extract of the original regesta, in the Vatican archives.
Other correspondence extant includes 38 letters of the antipope Anacletus II (1130-38).
Many of the above are not actual originals, which fact has been discerned by the science of diplomatics.
The regesta generally are of first historical importance, and have been published in three great collections, chief among which is that of Jaffe, Leipzig, 1888 (2nd edition).
New Catholic Dictionary