Because the egg was associated with rebirth and renewal, as early as the 5th BC. century

More than 2.500 years of symbolism for religion have the eggs that these days we dye red and crackle saying "Christ is Risen". Because indeed the egg was associated for millennia with rebirth and renewal, initially in the first days of spring, while it was subsequently adopted as a symbol of Christianity. And this is because the egg lends itself to the mental representation of the cycle of life, which for many plants and animals begins in spring.

The first historical evidence of egg symbolism in religion dates back to 500 B.C. In the Achaemenid period the Persian calendar was influenced by Zoroastrianism and the vernal equinox, the first day of their calendar year, it was a celebration, as we see in a relief from Persepolis (500 e.g.), where nobles are represented holding eggs in their hands. The vernal equinox is celebrated, in fact, even today by dyeing eggs and eating them.

The first one, in any case, attested use of the egg as a Christian symbol is placed in the Roman period. Roman religion, besides, had been greatly influenced by the treatises of Hippocrates, where the hatching of eggs was often referred to in comparison to the birth of humans. In "By the nature of a child", specifically, an infant being born, described in analogy to a little chicken breaking the eggshell.

During the 1st AD. century, the connection of the egg with burials is also found for the first time: In Rome, a child's tomb was found dating back to around 50-175 μ. X. and according to archaeologists, "under the left hand of the buried person there is a hen's egg, which in the funerary context is probably not simply a food offering, but perhaps also a reference to eschatological rebirth".

In the necropolis of the Vatican, moreover, a child was found buried with many gifts, including eggs! And here the excavators believe that the egg was probably a “symbol of rebirth, of a new life that would balance the injustice of an early end".

These two burials perhaps represent early Christian burial customs, as the egg was closely connected with the idea of ​​rebirth and this already from the years of Jesus Christ:Zoe, death, resurrection. As the great religious scholar Nilsson also mentions, "the egg is an apparently living and inert substance containing the possible beginning of a life, and that which has such life-giving power must necessarily awaken or nourish the life-forces of those to whom it is offered.".

Nevertheless, there is not much historical evidence linking the egg to Jesus. In the Bible the references are minimal, according to the orthodox tradition however, Mary Magdalene brought boiled eggs to Jesus' tomb. The eggs, on delivery always, they turned a bright red color, the color of blood, when she saw that Jesus had risen.

Another story tells how, when Mary Magdalene went to the Roman emperor Tiberius to tell him that Jesus had risen, he replied: "As long as Jesus was resurrected, so much so that this egg is red", but as soon as he finished his sentence the egg turned a vivid red color.

The spring, in any case, it is a time of celebration and signifies a new beginning, whether it is the beginning of the year, the liberation from the slavery of Egypt or the resurrection of the Savior.