Throughout the years the extent of the contributions by A. Dees to the renewal of philology, has become progressively more evident. In his Etudes sur l'evolution des demonstratifs en ancien et en moyen français (1971) Dees has developed a framework within which language evolution in the past can be reconstructed in detail. A comparison of the data of the two Atlases compiled by Dees with the manuals of Old French shows the extraordinary richness of these Atlases with respect to both the visual representation and the documentation not used previously. The first section of this Festschrift is devoted to language variation and distribution. The renewal of the stemmatology started by Dees goes back to the early 1970s. Dees proved that there is a mathematical solution to the problem of reconstructing a genealogical tree for a text. The application of this theory to manuscripts in various languages forms the second theme of this Festschrift.