Pappus of Alexandria was a late Greek geometer whose theorems provided a foundation for modern projective geometry. Virtually nothing is known about his life. He wrote his major work, Synagoge, or the Mathematical Collection, as a guide to Greek geometry. This collection of mathematical writings in eight books is thought to have been written around 340, although some historians believe that Pappus had completed the work by 325. Pappus' work discusses the theorems of more than thirty different mathematicians of antiquity, including Archimedes, Euclid, Apollonius, and Ptolemy.

Synagogeis important for two reasons. First, it was a type of concordance to the study of Greek geometry with historical interpretations and amendments to existing theorems. The initial purpose of the text was to allow the student to use the Synagoge as a supplement while the original works are read. He generalized the postulates and theorems of his predecessors, as with the Pythagorean theorem found in Euclid's Elements.

Secondly, Synagoge was composed in an era that witnessed the gradual decay of the classical world--it could thus be construed as an attempt on Pappus' part to preserve the mathematical traditions of the Greco-Roman world. The text chronicles many of the works of ancient mathematicians and philosophers. Although the first book and part of the second are lost, it is a highly valuable historical record of Greek mathematics.