Aristaeus the Elder (active 370 BCE300 BCE) was a Greek mathematician who worked on conic sections. He was a contemporary of Euclid, though probably older. We know practically nothing of his life except that the mathematician Pappus of Alexandria refers to him as Aristaeus the Elder which presumably means that Pappus was aware of another later mathematician also named Aristaeus. Pappus gave Aristaeus great credit for a work entitled Five Books concerning Solid Loci which was used by Pappus but has been lost. He may have also authored the book Concerning the Comparison of Five Regular Solids. This book has also been lost; we know of it through a reference by the Greek mathematician Hypsicles.

