Actually the myth that he was crucified upside down originates in the late 2nd century apocryphal book The Acts of Peter and susequent Clementine literature. Christian writers often erroneously believed some of what was in these obvious works of fiction to be true and repeated the information there as if true when it had no basis in history or reality.
It is a pure myth, probably invented by the disciples of Simon Magus who wanted their founder to be associated with Simon Peter and later venerated as him. And they were successful.
Since the bones of Peter [Simon Bar Jonah] are all intact and accounted for in his ossuary at the Monastery of Dominus Flevit on the Mount of Olives in Jerusalem where they were discovered in 1953, then Peter couldn't have died in Rome.
However it is entirely possible that Simon Magus was crucified upside-down by Nero there in Rome, and his body buried in that pagan cemetery with the other soothsayers on Vatican Hill. Since his mausoleum would have had to have been moved in order for Constantine to build St Peter's Basilica, his bones are more than likely in that tomb under the altar of the basilica. The Vatican should recheck those bones to see if they are the bones of a certain Samaritan sorcerer from Gitto.
And while a person who is crucified actually dies by suffocation, how exactly does someone who is crucified upside down actually die???? and why would the Romans diverge from their normal practice of capital punishment just because someone requests it???
BTW do Catholics have any idea what an UPSIDE DOWN CROSS actually symbolizes??? Do they realize that it is an occult symbol worn by soothsayers and sorcerers?
Why should we care what soothsayers and sorcerers think? They're nuts and evil and wrong.
It's a shame that someone of your obvious intelligence posted this.
http://www.seiyaku.com/customs/crosses/peter.html says that:
"Peter is believed to have been crucified upside down at his own request, as he did not feel worthy to die the same way as Jesus. Therefore many Christian sects use this cross as a symbol of humility.
He was an early missionary in Asia Minor and the Roman Empire and founded the Church of Rome with Paul, Emperor Nero saw this new church as a threat, and began a campaign to eradicate these troublemakers. Peter was imprisoned, tortured and finally crucified. Such was his faith, it is believed, he remarkably succeeded in persuading his sadistic captors to change from the normal way of executing prisoners. Apostle Andrew also was crucified, and he too requested that a cross different to Christ's Latin Cross be used. Therefore we have another cross form, the 'X' shaped St. Andrew's Cross.
In 1920, Archbishop Joachim of Nizhny Novgorod was also crucified upside down, on the Royal Doors of the Cathedral in Sevastopol, a Black Sea port of southern Ukraine.
Sometimes this cross is called Satan's Cross because it points downward to Hell. But this is a misnomer; Satan was never crucified on a cross, rather he fell to his death1. This inverted cross is sometimes used by Satanists to mock the Latin Cross and its meaning."
Step back a little. There is more to Heaven and Earth...
Simon Magus, also known as Simon the Sorcerer and Simon of Gitta, is the name used by the ancient Christian Orthodoxy to refer to a person identified as a Samaritan proto-Gnostic. The name was also used generically by ancient Christian Orthodoxy, to refer to a person who founded his own religious sect.