Imalo edno vreme, dating from 1957, is the earliest of Parashkev Hadjiev's operas and the one most often revived. It is a fairy-tale piece whose principal figures are Kalina and Radoyko, and the story keeps the shape of a folk tale rather than of a literary drama. Hadjiev wrote it in a deliberately accessible manner, with strophic numbers and dance rhythms, and it has served ever since as an introduction to opera for Bulgarian audiences, staged for children as often as for adults. Kalina's aria is among the few pieces of Bulgarian opera that circulate independently of the stage.