The following paragraph is taken from the "Catholic Almanac"

Simon: Called the Cananean or the Zealot; according to legend, preached in various places in the Middle East and suffered martyrdom by being sawed in two; in art, is depicted with a saw, the instrument of his death, or a book, symbolic of his zeal for the Law; Oct. 28 (Roman Rite). May 10 (Byzantine Rite). Taken from Otto Hophan, O.F.M Cap.

The apostle Simon was the least known, and one must constrain himself lest he say the least important, of all the apostles. In all Sacred Scripture there is nothing else said of him beyond the mention of his name. And even this name, Simon-from the Hebrew, shim'on, literally, "heard"-he had to share with another Simon in the circle of the apostles. The duplication of names among the apostles is surprising: Simon Peter and Simon the Zealot, James the Great and James the Less, Jude Thaddeus and Judas Iscariot. Simon Peter was the first, the great, the rock foundation of the Church. It would seem that the greatness of this first Simon completely overshadowed Simon, the unknown, the last of the Twelve.

http://www.12apostlesofthecatholicchurch.com/

Simon the Canaanite: Named in Luke and Acts as "Simon the Zealot". Also known as Simeon of Jerusalem