This is a belated addition to my journal about Arezzo and Perugia, which I said that I would attach to it and then forgot. The legend has to be one of the more curious emanations from medieval Christianity, but happily it inspired one of the greatest fresco cycles of the Italian Renaissance.
The legend is described in the Golden Legend, compiled by the Italian Jacopo da Varagine (or Jacobus de Voragine) in about 1260 and widely read in late medieval Europe.
The story begins in the Garden of Eden, when Adam dies at the considerable age of 930. He is buried by his son Seth, who plants a branch from the Tree of Knowledge (bizarrely) in his mouth.
Wood from the resultant tree finds its way to Jerusalem where it is used to construct a bridge. The Queen of Sheba visits King Solomon in Jerusalem where she worships the wood and avoids walking on the bridge, having had a vision that the wood would, essentially, be used at the crucifixion.
Some versions of the legend suggest that King Solomon had decided to use the wood in his temple, but the Queen of Sheba advised against this - foreseeing that it would cause trouble for the Jews. This caused Solomon to think better of his idea and he buried the wood.
The Romans did indeed use the wood for the crucifixion of Jesus.
Helena, mother of the Emperor Constantine, went to Jerusalem (in the 4th century). She found the three crosses used at the crucifixion - by having a man, who knew their whereabouts, put down a deep well until he decided to tell her. She was able to identify the right one because it caused the miraculous resurrection of a dead man.
The Persian king Khosrow II (or Chosroes II) removed the cross from Jerusalem, but it was recovered by the Byzantine Emperor Heraclius, who defeated Chosroes in battle in the 7th century. The Emperor in person returned the cross to Jerusalem, an event celebrated by the Roman Catholic Church as the Exaltation of the Cross.
Since then, many fragments are said to have found their way into churches and monasteries around the world. The 16th century Protestant theologian John Calvin famously remarked that there was enough wood in all the relics to fill a ship.
Piero della Francesca (c1415-1492) depicts the legend in the famous fresco cycle in the church of San Francesco in Arezzo, eastern Tuscany.
Evelyn Waugh's only historical novel " Helena and the True Cross" recounts the legend much as set out in Tony's account. Waugh thought that this was his greatest novel but few other people agree with him.