Catechismus in der windischenn Sprach or simply Catechismus (Catechism, also known as Katekizem v slovenskem jeziku or simply Katekizem in modern Slovene), is a book written by the Slovene Protestant preacher Primož Trubar in 1550.[1] Along with Trubar's 1550 book, Abecedarium (Abecedary), Catechismus was the first book published in Slovene.[1] Catechismus served as part of a foundation of the establishment of a national identity for Slovenes.[1]