Verfassung von Tarnowo
In 1908, when Prince Ferdinand Saxe-Coburg-Gotha proclaimed the independence of Bulgaria, he raised the country to a kingdom and assumed the title "tzar" (translated as king outside of Bulgaria). The Tarnovo Constitution was amended to change the official name of the country to the "Kingdom of Bulgaria" and substituting the word "Prince" with "tzar" wherever it occurred throughout the document.