Slovenia presents one of the sharpest gaps in Europe between affiliation and practice. A substantial share of the population records itself as Catholic; regular attendance is among the lowest in Catholic Europe, and the number declining to state any religion has grown steadily.
The Slovene Reformation left almost no churches and almost no congregations, because the Counter Reformation under the Habsburgs removed both, expelling preachers and burning books. What it left instead is the language. Primoz Trubar, a Protestant preacher working in exile, printed the first two books in Slovene in 1550, a catechism and an abecedarium, and went on to translate the New Testament. Jurij Dalmatin completed a full Slovene Bible in 1584, and Adam Bohoric published the first Slovene grammar the same year. That output is treated as the foundation of the literary language, which is why a Catholic country marks Reformation Day as a public holiday and puts a Protestant preacher on its currency and its stamps.
There is a small continuing Protestant presence in Prekmurje in the northeast, which was under Hungarian rather than Austrian rule and where Lutheranism survived.
The post independence settlement has been contested. Property nationalised under Yugoslavia was returned through a denationalisation process that produced years of litigation and public argument, particularly over forest and land holdings. Religious instruction is excluded from state schools, an arrangement the Catholic Church has challenged and that has held. A financial collapse in the Maribor archdiocese in 2013, arising from speculative investments, led the Vatican to remove its senior clergy and did considerable reputational damage.