The origin

The origin of the pseudo-Galenic treatise circulating under the titles  De spermate/Microtegni/De XII portis etc. is not known. It may have been composed in late antiquity and transmitted to the Latin West through Arabic. Kudlien argues for a possible origin in the Neoplatonist circles connected with the school of Alexandria, where some forgeries of Galen were apparently produced around the third century. The text might also be a compilation made in Latin in the eleventh or twelfth century.  It seems to be based on several earlier sources, citing a variety of ancient medical and philosophical authors, including references to works ascribed to Hippocrates and Aristotle. There is nothing in the contents to suggest that the compiler would have drawn his information directly from Galen's authentic text. The earliest manuscripts were written in England (London, BL, Cotton Galba E IV, mid-twelfth c.) and S. France (Paris, BNF, lat. 15114, mid-twelfth c.) as well as S. Germany (Munich, clm 18918 and clm 4622, late twelfth c.).  At the end of the twelfth century the text was ascribed to Galen as author and Constantine the African as translator, and a new title, Microtegni, evoking Galen's Ars parva, was added. Galen's authentic Peri spermatos, had been translated into Syriac by the well-known translator Hunain ibn Ishaq (aka Johannitius) in 840-1, into Arabic maybe by one of his pupils, and into Latin as late as the beginning of the fourteenth century by Niccolò da Reggio. In Latin manuscripts Galen's authentic text also occurs under the title De spermate. In modern scholarship the Latin translation of the authentic Peri spermatos is commonly referred to as De semine, but even some modern texts the titles De spermate and De semine are used for both texts, which continues to create confusion.