The Haabʼ (Mayan pronunciation: [haːɓ]) is part of the Maya calendric system.
Bricker (1982) estimates that the Haabʼ was first used around 500 BCE with a starting point of the winter solstice.
Inscriptions on The Temple of the Cross at Palenque shows clearly that the Maya were aware of the true length of the year, even though they did not employ the use of leap days in their system of calculations generally.
J. Eric Thompson[4] wrote that the Maya knew of the drift between the Haabʼ and the solar year and that they made "calculations as to the rate at which the error accumulated, but these were merely noted as corrections they were not used to change the calendar."
The five nameless days at the end of the calendar, called Wayebʼ, was thought to be a dangerous time.