Phantom Time Hypothesis\conspiracy theory

Phantom time hypothesis is a theory that says that European history between AD 614–911 is a forgery by the Roman Catholic Church. The theory was suggested by Heribert Illig in 1991 and expanded by other theorists.

Theory
The original reasoning behind the theory was that when the was introduced in 1582, the difference between it and the old  should have been 13 days, but the calender was only "rewound" 10 days forward. These three days roughly correspond to 300 years. This argument was later countered by the consideration that the Gregorian calender was synchronized not with AD 1 but with AD 325, when the took place, thus accounting for the "missing" three centuries.

Furthermore, Illig claimed that the archaeological finds that can be reliably dated to the period of 7th-10th centuries are very scarce. He also argued that (approx. 10th century AD) couldn't have emerged much later than five centuries after the  (5th century AD). He then concluded that conspired with  to retroactively invent the entire  including.

No attempts to synchronize this theory with alternative calenders e.g. or  are documented.