h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Does anybody know when the sign of the fish, when relatated to Christ, was replaced by the sign of the cross?

the cross was used as a triumphal symbol at ravenna in about the 5th century. this followed the conversion of emperor constantine(i think, someone roman any way) and the church became a part of the state. the symbol of the cross had been evident in other cultures, cypriot pottery figures for example.

and interesting thing to note, during the exodus in the old testament, the nation of isreal arranged themselves around the "ark of covenent". This arrangement formed a cross (one with similar if not the same dimensional ratios as the cross that many associate with christianity) when viewed from an arial view (due to the size of each tribe in the arrangement)