Following the death of Pope Clement IV, was the longest papal election in the history of the Catholic Church. This was due primarily to political infighting between the cardinals.
This is called an Interregnum. Not considered a break in the line of popes.
What about Anti-Popes.
An anti-pope is someone who is opposed to another legally elected pope. Now, as many of you know we have had about 40 anti-popes all through the centuries.
You will find, however, that an anti-pope can still be a Catholic and continues to belong to the church. As a matter of fact the first anti-pope actually became a Saint, St. Hippolytus of Rome (217-235 AD).
During the western schism, which really wasn’t a schism, we had three popes for about thirty years. To begin with this to was more about politics and not matters of faith. So we had two anti-popes and one true pope at this time. Even if you did not know which Pope was the real pope, this does not constitute a break in the LINE.
Once the division came to an end all the participants remained in the church, therefore, you could not label or call these anti-popes ‘AntiChrists.’
The Man of Sin.
Once Paul VI became a formal, public, heretic, officially, on November 19, 1969, when he publicly rejected the pleas of the Traditionalists and the Ottaviani Intervention, he became automatically excommunicated and there was no papal election to replace him. Therefore the line of popes was broken in violation of Vatican Council I, which teaches Papal Infallibility and Perpetuity of the Papacy. As a result of this action, Paul VI identifies with the Biblical “Man of Sin,” in II Thessalonians 2. Which in turn, instituted the “Great Apostasy,” (Schism) and the Reign of AntiChrists which can only be concluded with the Second Coming of Christ on judgment day, the last Pentecost Sunday.