Sts Cyril and Methodius Day

July 5 is a public holiday in Slovakia (and Czechia). It is Sviatok svätého Cyrila a Metoda, the day to commemorate Saints Cyril and Methodius. These two saints are significant in Slavic lands and indeed are called the “Apostles to the Slavs”. As far as I know, in Slovakia it’s not celebrated any specific way aside from the church that honors them. Still, they are vastly important.
Why are they so special to the Slavic people and what specific connection does Slovakia play?

