In the city of Uppsala, located at some 70km-distance from the Stockholm Archipelago, the average wind-speed throughout the year is 10–15 kilometers per hour. These dynamics generate recurring spectacles of ‘turbulent’ skies, as clouds are constantly in motion and they rapidly form, reform and transform the image of the sky. These spectacles make this Byzantinist reflect upon ways in which medieval people—who had never flown a plane, bound to the land—would have been receiving them in their everyday life. How ‘heavenlily-induced’ would they have considered turbulent skies? Would they have understood the image on the cover of this book (a cloud-pattern depicting a long staircase leading from the low parts of the horizon to the celestial hights) as divine invitation? The turbulent skies of Uppsala have nurtured me with ample imagination towards understanding medieval hagiographical texts and writing this book