Staurogram


The staurogram, also monogrammatic cross or tau-rho, is a ligature composed of a superposition of the Greek letters tau and rho.

Early occurrence and significance

Abbreviation for ''stauros''

The staurogram was first used to abbreviate stauros, the Greek word for cross, in very early New Testament manuscripts such as P66, P45 and P75, almost like a nomen sacrum, and may visually have represented Jesus on the cross.

Monogram of Christ

The Tau-Rho as a Christian symbol outside its function as nomen sacrum in biblical manuscripts appears from c. the 4th century, used as a monogramma Christi alongside the Chi-Rho and other variants, spreading to Western Europe in the 5th and 6th centuries.

In combination with alpha and omega

discusses a Christian symbol, apparently combining the Tau-Rho with Alpha and Omega placed under the left and right horizontal arms of the Tau.
Ephrem says that the Tau represents the cross of Jesus, the Alpha and Omega signify that the crucified Christ is "the beginning and end", and the Rho, finally, signifies "Help", because of the
numerological value of the Greek word being 100, represented by Rho as a Greek numeral.

Tau and rho separately

The two letters tau and rho can be found separately as symbols already on early Christian ossuaries. Tertullian explains the Tau as a symbol of salvation by identification with the sign which in was marked on the forehead of the saved ones.
The rho by itself can refer to Christ as Messiah because Abraham, taken as symbol of the Messiah, generated Isaac according to a promise made by God when he was one hundred years old, and 100 is the value of rho.

Coptic Unicode block

The staurogram is encoded by Unicode in the Coptic block, at , and as of Unicode 7.0 also in the Ancient Symbols block, at . The Coptic block has a ligature of the full word σταυρός, where the τρ is represented by the staurogram, and two lunate sigmas are attached to either side of the tau's horizontal bar, at .