Although it was very small , Saxe-Hildburghausen was an independent duchy from 1680 to 1826 . In 1684 the duchy changed its capital from Heldburg to Hildburghausen , and changed its name to Saxe-Hildburghausen . Despite its tiny territory , this was an autonomous duchy from 1680 to 1826 ; in 1684 the capital was moved from Heldburg to Hildburghausen , and the mini-state became known as Saxe-Hildburghausen .