The beginnings of the Ljubljana diocese date back to the end of the Middle Ages. It was in 1461 that Emperor Frederic
III assigned to his newly founded and from Aquileia independent diocese the parishes under his patronate, most of which had
been part of the Counts of Celje heritage. The Emperor's foundation was confirmed on the 6th of September 1462 by Pope
Pius II. The Ljubljana diocese consisted of five disconnected territorial areas within the Austrian provinces of Carniola,
Syria and Carinthia. Under Emperor Joseph II, between the years 1785—1788, the diocesan borders were rearranged,
flowever, it was only in the 19th century that its borders finally became identical with those of the province of Carniola. This
was at the same time its largest extent. On the basis of the Franciscean land cadastre kept in the Archive of the Republic of
Slovenia, the author defines the extent of the parishes in question.