Since the publication of the Supplementa altera to the Aristoteles Latinus catalogue volumes (1961), many more manuscripts have come to light and more detailed descriptions were published. The study of fragments, both detached and in site, brought many additional discoveries. The finds were randomly issued in periodicals, library catalogues, or auction catalogues. Other manuscripts that were included in the AL catalogue volumes, particularly those kept in private collections, later changed owner or location. No systematic attempt to catalogue AL manuscripts has been undertaken in the last decades. The following pages contain a preliminary version of the eventual on-line Supplementa tertia. Apart from the manuscript’s location, shelf mark, and content, the description lists its date, measurements (in centimetres), the number of folios, and the original AL catalogue number where available. A hyperlink is provided for those manuscripts for which images can be found in the public domain.