Pappus of Alexandria was a Greek mathematician of late antiquity known for his Synagoge (Συναγωγή) or Collection, and for Pappus's hexagon theorem in projective geometry. Almost nothing is known about his life except for what can be found in his own writings, many of which are lost. Pappus apparently lived in Alexandria, where he worked as a mathematics teacher to higher level students, one of whom was named Hermodorus. 290 – 350; died at about 60. Alive at the same time as Constantine the Great, Ambrose, Porphyry, Ausonius, and Julian. Wiki link