ROME, 13 SEPT. 2011 (ZENIT)
Answered by Legionary of Christ Father Edward McNamara, professor of liturgy at the Regina Apostolorum university.
Q: A Mass server recently told me that he has observed that the crucifix on the Holy Father's chair is turned upside down. It is true? If yes, why? I have not observed that myself. — D.K., Accra, Ghana
A: In all probability what your server observed was a Petrine cross and not a crucifix.
The use of the symbol of the inverted Latin cross stems from an ancient tradition that St. Peter requested to be crucified upside down as he felt unworthy to die in the same manner as his Lord. There is written evidence of this tradition from before the year A.D. 200.
An analogous tradition has St. Peter's brother, St. Andrew, also requesting to be crucified in a distinctive manner. From his death comes the X-shaped St. Andrew's Cross. This cross is represented on the Jamaican and Scottish flags and, along with St. George's and St. Patrick's crosses, on the flag of the United Kingdom commonly called the Union Jack.
Since the Pope is Peter's successor, the inverted cross is a relatively frequent symbol of the Petrine office along with other symbols such as the keys and the triple tiara. For example, such a cross is found in St. Peter's on the brick wall that seals off the Holy Door until the next jubilee year. Also, when Blessed John Paul II visited Israel he used a chair with a Petrine cross on the back. It is quite possible that other papal chairs repeat this motif.
As far as I know, when this cross is used as a symbol it never contains the crucified figure of St. Peter. It is true that the Vatican contains several representations of the apostle's crucifixion, such as that found on St. Peter's Basilica's bronze central door, cast by Filarete in 1445. These, however, are historical figurations rather than religious symbols.
The use of an inverted crucifix with the figure of Christ attached is something entirely different. At the very least it is disrespectful and is often considered as a satanic or anti-Christian symbol. Certainly, some denizens of popular culture have used it in films, music videos, album covers and stage costumes to represent Satan or the Antichrist.
Among some pagan groups a particular form of upside-down cross can represent the Icelandic and Nordic symbol of the hammer of Thor.