Collectio Grimanica
The Collectio Grimanica is a collection of letters of Leo the Great extant in only one manuscript of the ninth century, namely Paris, Bibliothèque Mazarine, 1645. It contains 104 letters, more than any other medieval collection of Leonine letters, and is chronologically arranged. According to Turner, it was composed in the sixth century; Silva-Tarouca, in contrast, argued it was influenced by many collections including Pseudo-Isidore and thus late. However, as Jasper relates, this view has not won acceptance; rather, the False Decretals are thought to have been influenced by the Grimanica. Schwartz used it for his edition of Leo's letters, but both Jasper and Hoskin (and indeed others) see the readings of the Grimanica as less valuable.
Literature
Jasper, pp. 41 n. 173, 47-49, 56, 145; Hoskin, Letters pp. 267-268.