Sebastian Krelj, also known as Sebastjan Krelj, Sebastijan Krelj or Boštjan Krelj (1538–1567) was a Slovene Protestant reformer, writer, theologian, linguist and preacher and regarded as one of the most educated Slovene Protestants of the 16th century[1]..
Krejl was born in Vipava, then part of the Duchy of Carniola. He studied at University of Jena and became a follower of the Lutheran preacher and author Primož Trubar, the leader of the Protestant Reformation in the Slovene Lands, whom he assisted as a preacher in Ljubljana. Krelj had a wide linguistic and philologic knowledge: besides Slovene, German and Latin, he knew Ancient Greek, Hebrew, Croatian and glagolitic literature. Krelj put the central dialect into context of dialects spoken by Istrians, the inhabitants of the Vipava Valley and Lower Carniolans. He identified and used the signs: s, z, c, š, ž, č, and his reforms were taken up by Dalmatin in the bible [1].
In Ljubljana he later became superintendent of Slovenian Protestant Church.