Remove all predefined holidays.
(with-eval-after-load 'calendar
(setq holiday-general-holidays nil
holiday-solar-holidays nil
holiday-bahai-holidays nil
holiday-christian-holidays nil
holiday-hebrew-holidays nil
holiday-islamic-holidays nil
holiday-oriental-holidays nil))
Define the public holidays in Slovakia.
(with-eval-after-load 'calendar
(setq holiday-local-holidays
'((holiday-fixed 01 01 "Establishment of the Slovak Republic")
(holiday-fixed 01 06 "Epiphany")
(holiday-fixed 05 01 "International Workers' Day")
(holiday-fixed 05 08 "Victory over fascism")
(holiday-fixed 07 05 "Saints Cyril and Methodius")
(holiday-fixed 08 29 "Slovak National Uprising")
(holiday-fixed 09 01 "Constitution Day, 1992")
(holiday-fixed 09 15 "Day of Our Lady of the Seven Sorrows")
(holiday-fixed 11 01 "All Saints' Day")
(holiday-fixed 11 17 "Struggle for Freedom and Democracy")
(holiday-fixed 12 24 "Christmas Eve")
(holiday-fixed 12 25 "Christmas Day")
(holiday-fixed 12 26 "St. Stephen's Day")
(holiday-easter-etc -2 "Good Friday")
(holiday-easter-etc +1 "Easter Monday"))))