Legend of the True Cross (fresco cycle in Arezzo)

In the main choir chapel (Cappella Maggiore) of San Francesco, the Franciscan church in Arezzo, Piero della Francesca painted a fresco cycle narrating the stories of the True Cross (the cross on which Christ was crucified). The subject-matter of the stories illustrated by Piero is drawn from Jacobus de Voragine's "Golden Legend", a 13th century text that recounts the miraculous story of the wood of Christ's Cross. The story tells how Adam, on his deathbed, sends his son Seth to Archangel Michael, who gives him some seedlings from the tree original sin to be placed in his father's mouth at the moment of his death. The tree that grows on the patriarch's grave is chopped down by King Solomon and its wood, which could not be used for anything else, is thrown across a stream to serve as a bridge. The Queen of Sheba, on her journey to see Solomon and hear his words of wisdom, is about to cross the stream, when by a miracle she learns that the Saviour will be crucified on that wood. She kneels in devout adoration. When Solomon discovers the nature of the divine message received by the Queen of Sheba, he orders that the bridge be removed and the wood, which will cause the end of the kingdom of the Jews, be buried. But the wood is found and, after a second premonitory message, becomes the instrument of the Passion.

Three centuries later, just before the battle of Ponte Milvio against Maxentius, Emperor Constantine is told in a dream, that he must fight in the name of the Cross to overcome his enemy. After Constantine's victory, his mother Helena travels to Jerusalem to recover the miraculous wood. No one knows where the relic of the Cross is, except a Jew called Judas. Judas is tortured in a well and confesses that he knows the temple where the three crosses of Calvary are hidden. Helena orders that the temple be destroyed; the three crosses are found and the True Cross is recognized because it causes the miraculous resurrection of a dead youth. In the year 615, the Persian King Chosroes steals the wood, setting it up as an object of worship. The Eastern Emperor Heraclius wages war on the Persian King and, having defeated him, returns to Jerusalem with the Holy Wood. But a divine power prevents the emperor from making his triumphal entry into Jerusalem. So Heraclius, setting aside all pomp and magnificence, enters the city carrying the Cross in a gesture of humility, following Jesus Christ's example.