The theory that Albanians were related to the Illyrians was proposed for the first time by the Swedish historian Johann Erich Thunmann in 1774. The scholars who advocate an Illyrian origin are numerous. There are two variants of the theory: one is that the Albanians are the descendants of indigenous Illyrian tribes dwelling in what is now Albania. The other is that the Albanians are the descendants of Illyrian tribes located north of the Jireček Line and probably north or northeast of Albania.