The earliest classifications of plants were based on whether the plant was considered medicinal or was shown to have other uses. De re Rustica by Roman statesman Marcus Porcius Cato (also known as Cato the Censor or Cato the Elder, 234–149 B.C.E.) lists 125 plants and was one of the earliest catalogs of Roman plants. Roman author and naturalist Gaius Plinius Secundus (23–79 C.E.), known as Pliny the Elder, wrote Historia Naturalis; published in the first century, it was one of the earliest significant plant catalogs in the ancient world, describing more than 1,000 plants. Plant classification became more complicated as more and more plants were discovered. One of the earliest plant taxonomists was the Italian botanist Caesalpinus (1519–1603). In 1583, he classified more than 1,500 plants according to various attributes, including leaf formation and the presence of seeds or fruit.