The festival’s website and full schedule is here.
The festival which focuses on classical music goes back to 1988, when an association was set up in a bid to revive "the cultural image" of Ljubljana's historical centre.
The idea to take music to squares and churches of the Mediaeval Ljubljana was given by acclaimed musician and Ljubljana Music Academy professor Primož Lorenz (1944-2007).
The project has grown to embrace 20 Slovenian towns in Slovenia and its neighbours, expanding further abroad, its organisers said in a press release.
Tonight's concert of Russian Cossack songs and dances will be symbolic in that it draws on Imago's beginnings.
"A similar spectacle was one of the first bigger events involving foreign performers organised by our institution.
"The opening of this year's festival is thus a memory of a time when Imago Sloveniae started to enter the international arena," the organises say on their website.
The Russian Cossacks State Dance Company is a leading professional dance group in Russia, cherishing traditional dance, songs and instrumental music.
Its Ljubljana concert was organised together with the Ljubljana-based Forum of Slavic Cultures, an international institution promoting Slavic-speaking countries.
Among this year's highlights the organisers pointed to a concert by Icelandic violinist Judith Ingolfsson and Russian-born pianist Vladimir Stoupel and another by Belarusian flutist Maruta Staravoitava.
A concert of organ and violin music termed From Baroque to Romanticism will be played by Russian-born Slovenian violinist Vasilij Meljnikov and Russian organ virtuoso Irina Rozanova.
Famous Slovenian mezzo-soprano Bernarda Fink will sing together with the men's choir Ljubljana Vocal Academy, which is celebrating its 10th anniversary.
Several up-and-coming musicians will give concerts as part of the Young Talents series and the Jazz Stage series will feature some exceptional musicians of world renown.
The festival’s website and full schedule is here.
