True Cross significant event Crucifixion of Jesus
The True Cross is said to be the real cross that Jesus of Nazareth was crucified on, according to Christian tradition. 
It is related by numerous historical accounts and legends, that Helena, the mother of Roman Emperor Constantine the Great, recovered the True Cross at the Holy Sepulchre in Jerusalem, when she travelled to the Holy Land in the years 326–328. The late 4th-century historians Gelasius of Caesarea and Tyrannius Rufinus wrote that while she was there, she discovered the hiding place of three crosses that were believed to have been used at the crucifixion of Jesus and the two thieves, Dismas and Gestas, who were executed with him. To one cross was affixed the titulus bearing Jesus' name, but according to Rufinus, Helena was unsure of its legitimacy until a miracle revealed that this was the True Cross. This event is celebrated on the liturgical calendar as the Feast of the Exaltation of the Cross.
The Catholic Church, Eastern Orthodox Church, Oriental Orthodox Church, and the Church of the East all claim to possess relics of the True Cross as objects of veneration; while Protestant and other Christian churches generally dispute the authenticity of the relics, and do not hold them in high regard.