Geoponika, a compilation of advice on agriculture put together about ad 950 at the behest of the scholarly Byzantine Emperor Constantine VII Porphyrogenitus, as part of a grand scheme of digests of knowledge. It may have been based on a compilation of some three centuries earlier by Cassianus Bassus. Of the 20 books, the largest section, Books 4โ8, consisted of a long list of precepts on viticulture and winemaking. It survives in part. The information is of variable quality. Much can be traced back to the Roman agricultural treatises but it includes material from authors, particularly of the Hellenistic period, whose work is otherwise unknown to us.