Metemptosis

The Metemptose (from Greek. Ἐμπίπτειν empiptein , fall into it) called the Gregorian calendar , the switching rule according to which the leap days every year whose number is divisible by 100 (ie 1700, 1800, 1900, etc.), failed, while they where which are divisible by 400 (i.e. 1200, 1600, 2000, etc.) remain.