Duchy of Saxe-Altenburg
In 1528 the Hildburghausen citizens turned Protestant. The town fell to the newly established Duchy of Saxe-Coburg in 1572 and upon the extinction of the line in 1638 passed to the Duchy of Saxe-Altenburg. In 1680 it became the residence of the Ernestine dukes of Saxe-Hildburghausen until its dissolution in 1826, after which it passed to the Duchy of Saxe-Meiningen. The town became part of the new state of Thuringia in 1920.