In Limbo Dante encounters a group of philosophers:
When I had raised my eyes a little higher, I saw the master of the men who know seated in philosophic family.
There all look up to him, all do him honor: there I beheld both Socrates and Plato, closest to him, in front of all the rest;
Democritus, who ascribes the world to chance, Diogenes, Empedocles, and Zeno, and Thales, Anaxagoras, Heraclitus;
I saw the good collector of medicinals, I mean Dioscorides; and I saw Orpheus, and Tully, Linus, moral Seneca;
and Euclid the geometer, and Ptolemy, Hippocrates and Galen, Avicenna, Averroes, of the great Commentary.