Theophrastus, philosopher and botanist

Theophrastus lived in Alexander’s days, but despite his elaborate work on the plants and foods he received from Asia, he is hardly mentioned in this context.

Theophrastus was born around 371 BC in Lesbos and was given the name of Tyrtamus. When he was 17 years old, he became a disciple of  Aristotle who changed his name into Theophrastus (spoken by God) because of his exceptional eloquent language. Together they traveled to Lesbos in 347 BC to study the animals and plants of the island.

When Aristotle left for Macedonia to teach the young prince Alexander, Theophrastus continued his botanical study. Yet, the relationship between Aristotle and Theophrastus remained very close, and we may wonder which part each of them played in analyzing and studying the many plant and seed specimens Alexander sent back from Asia.

It is known that Theophrastus maintained a botanical herbarium, something unusual for the time. The array of plants he studied came from Persia, Afghanistan, and the Indus Valley. He introduced the Greeks to the robust argun palms, bananas, citrons, cardoons (or artichoke thistle), mangos, jujubes (also called Chinese dates), pistachios, and tamarind. Pepper arrived in Athens at some time in the 4^th century BC, maybe carried along by Alexander’s troops. Newly imported plants were cinnamon, banyan (a fig typically from India), as well as frankincense and myrrh (the myrrh trees in Gedrosia were taller than anywhere else and Alexander’s mercenaries from Phoenicia readily collected it). Cotton was another novelty that appeared in the Greek world and some say that is was Theophrastus who brought cotton to this country, but his role in this matter is far from clear.

Upon the death of Aristotle in 322 BC, just one year after Alexander’s, Theophrastus inherited his mentor’s entire library, including his manuscripts. Drawing on Aristotle’s concepts and no doubt on his own experiences, he wrote two botany textbooks: the ten-volume Historia Plantarum (Inquiry into plants) and the eight-volume De Causis Plantarum (On the Causes of Plants) covering 550 species in all. Pliny the Elder based his Historia Naturae (Natural History) on Theophrastus' books, which remained primary references throughout the Middle Ages. Great men like Cicero and Seneca often leaned on Theophrastus’ knowledge.

According to Diogenes Laërtius, Theophrastus wrote 227 books, most of which are unfortunately now lost. Ptolemy II, the son of Ptolemy I Soter who had campaigned with Alexander, fully appreciated both Aristotle and Theophrastus, and he transferred their entire collection to Alexandria.

In his long life, Theophrastus worked as a lecturer at the Lyceum in Athens, enlarging and reorganizing the school over time. From the age of 49 until his death at 85, he taught a total of at least 2,000 pupils. He also founded a museum in Alexandria in memory of Aristotle.

[Picture of Theophrastus from NNDB]