Chi - Rho
The Chi Rho is one of the earliest symbols used by Christians dating from the 4th century. It is formed by superimposing the first two letters of the word "Christ" as it appears in Greek. Chi forms an "X" shape and Rho resembles a shepherds staff. Although not technically a cross, the Chi Rho invokes the crucifixion of Jesus as well as symbolizing His status as the Christ. It often appears with the Greek letter alpha on one side and the greek letter alpha on the other.