The Roman historian Marcius Terentius Varro (116-27 BC) was one of the most significant and productive ancient authors. He was a military leader under Pompey (106-48 BC), captured after the Battle of Pharsalus (48 BC) by Julius Caesar (100-44 BC), but was then appointed as the imperial librarian. His extensive works cover a wide range of topics such as grammar, geography, education, natural sciences, philosophy, and law. The Roman rhetorician Marcus Fabius Quintilian (35-96) referred to him as the "most learned of all Romans." Of his complete works, only "De re rustica" (also Res rusticae = On Agriculture) has survived in its entirety. He wrote it at the advanced age of 80 and dedicated it to his wife, who owned a country estate. The first of the three volumes describes agriculture, which also includes viticulture. The other volumes mainly deal with animal husbandry. Varro cites the Carthaginian Mago (500 BC) as his main source and mentions his work. He also cites Xenophon (426-355 BC), Aristotle (384-322 BC), and Cato (234-149 BC) as additional sources. Practical advice is given in a polished style and in dialogue form, often referring to the "good old days" when there were only honest, hardworking country folk and no urban decadence. In his opinion, wines should be at least one year old, particularly attributing aging potential to the Falerner. Later Roman authors such as Vergil (70-19 BC), Pliny the Elder (23-79 AD), Columella (1st century), and Palladius (4th century) used his work as a source. Parts are also included in the famous agricultural compilation Geoponika from the 10th century. See also under Ancient Grape Varieties and Ancient Wines.