No way this is true.

One of the wilder things that has been proposed in Medieval history is the idea that about 300 years in the Middle Ages was simply made up. Gap of history and phantom time. Proposed by Heribert Illig in 1991, the idea is that the Catholic Church, led by Pope Sylvester II, rewrote the calendar to put themselves at 1000 AD, rather than around 700 AD. As a result, the years 614 - 911 are simply made up. If this were true, historical figures such as Charlemagne were simply made up.