The Monogramma Christi, or Christogram, is a monogram made from a combination of chi and rho, the first two letters in Χριστός, or Khristos, the Greek name from which we get Christ. This symbol, which also resembles a figure on a cross, has been used since the third century as a symbol for Christ. The story is that God revealed to the Emperor Constantine that he would lead his armies under this symbol. Today the symbol can still be found in religious art and architecture. Kevin Walter nailed this to a cross in his sculpture Crucified Chi Rho. This was an entry in the 2010 MOC Athalon contest in the 'conceptual' category.