The mid-2nd century pope Anicetus (156-166) said that Peter was beheaded by Nero in Rome. The reason for this claim was that he had became locked in a conflict with the venerable Polycarp of Smyrna. Polycarp had tried to win the argument by insisting that he spoke with the authority of the apostle John. In response, Anicetus told of Peter's beheading and said that he spoke with the authority of Peter.

In the third century, the Church Father Origen changed the story somewhat, saying that Peter, condemned to crucifixion, felt himself unworthy to be crucified the same way as his Lord, and so chose crucifixion upside down.

I suppose it would depend on if you subscribe to Catholic dogma or not. I do not believe Peter was allowed to choose being crucified in this manner and rather that if it was done, it was done as a mockery to him and the early church.

Some people did adopt the symbol and assign their meaning to it, whatever the case may be. Aleister Crowley believed the inverted cross to be a symbol of inverted grace, or falling away from Christ's grace.

The cross is older than Christianity and the inverted cross is also a sign of the sword, war and bloodshed. There is also the matter of the sword of Mithras.

Christianity is a nascent faith that "borrows" from much older religions and philosophies.

Bottom line, there are no immaculate historical sources that prove how Peter died.

As far as "true" Satanic symbols go, I couldn't care less as I'm not a Satanist. Many embrace that label as a quick fix to be being unique. LaVey himself bemoaned this phenomena not long after the CoS was founded. One day you're Joe and the next Lord Azarel of Higher Hell. I've no use for it. The authority of the CoS means about as much to me as the authority of the Catholic church does.

Traditionally, Christian faiths have often dubbed anything outside of their system and "truth" to be Satanic. LaVey once said, "They named us."

Yes, I do find the occult interesting and entertaining. I do not take it seriously.

I subscribe to no religions; Eastern, Western or New Age. I do not accept any one philosophy wholesale either; I'm eclectic.

I felt like rambling in regard to your tweet, so there ya' go.