Pappus of Alexandria, one of the last great Greek mathematicians of antiquity, observed an eclipse that allowed historians to calculate the approximate dates of his life. Pappus of Alexandria: 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. October 18, 320. Wiki link