Dated 1564, the copy of one of the landmark works of the main figure of Slovenian Protestantism would fill the void in the series of early protestant heritage curated by the National and University Library (NUK).

The ministry will strive to exhibit the copy in Slovenia next year to mark the book's 450th anniversary, the ministry said in a press release.

The "Church Order" (Cerkovne ordninge), was published by the Slovenian Protestant minister and reformer in Germany and contains Trubar's vision of a legal, organisational and spiritual framework for the Protestant Church in Slovenia.

It is also valued for its language quality - Trubar is considered the father of the Slovenian language - since it was meant above all for the period's intellectual elite.

The book was banned as part of Counter-Reformation supported by Charles II and Trubar was exiled. The only copy believed to have survived so far - another was destroyed or lost in Dresden during WWII - was discovered in the Vatican library in 1971, it is said to be in poorer shape than the newly found one.

The existence of the third copy was revealed in October after it was coincidentally discovered by researcher Dieter Oppitz.