Abstract
"Frýdlantsko" is the name of specific administrative structure created within the Czech state during the Thirty Years' War. It received the status of principality (1624) and later duchy (1628).
It was a product of indisputable organizing genius (as well as excessive and unscrupulous ambitions) of Emperor's generalissimo Albrecht of Valdštejn. Intimately connected with its creator, this duchy, called by its contemporaries "lucky land (terra felix)" perished after Valdštejn's elimination in the year 1634, so its history is restricted on only one decade.