So, the theory is that between 46BC and 1582AD, we lost a day each century. This totals up to 16.28 days lost. However, it is claimed that it was 13 days out ERROR NUMBER ONE. Then, Pope Gregory the thirteenth corrected it by 10 days in the Gregorian calendar STILL 6.28 DAYS LEFT. Over the 4.32 centuries between then and 2014, we have only missed out 27.1296 DAYS, 6.28 days per century. This is nowhere near the proposed 300 years.
The maths not involved in this theory |