Wenceslaus I, Duke of Bohemia in the context of "Good King Wenceslas"

The Duchy of Bohemia, also later referred to in English as the Czech Duchy, (Old Czech: Češské kniežěstvie) was a monarchy and a principality of the Holy Roman Empire in Central Europe during the Early and High Middle Ages. It was formed around 870 by Czechs as part of the Great Moravian realm. Bohemia separated from disintegrating Great Moravia after Duke Spytihněv swore fealty to the East Frankish king Arnulf in 895.

While the Bohemian dukes of the Přemyslid dynasty, at first ruling at Prague Castle and Levý Hradec, brought further estates under their control, the Christianization initiated by Saints Cyril and Methodius was continued by the Frankish bishops of Regensburg and Passau. In 973, the Diocese of Prague was founded through the joint efforts of Duke Boleslaus II and Emperor Otto I. Later Duke Wenceslaus I of Bohemia, killed by his younger brother Boleslaus in September 935, became the land's patron saint.

Boleslaus I (Czech: Boleslav I. Ukrutný; 915–972), a member of the Přemyslid dynasty, was ruler (kníže, "prince") of the Duchy of Bohemia from 935 until his death in 972. He is notorious for the murder of his elder brother Wenceslaus I, through which he became duke. As duke, his decisions surrounding his dynasty led to the Roman Catholic conversion of Poland, which in turn led to the recognition of the Polish state by the papacy. This recognition helped to define medieval Poland as one of the first modern states.

Boleslaus I is generally respected by Czech historians as an energetic ruler who significantly strengthened the Bohemian state and expanded its territory. This perspective is fairly modern, as Boleslaus was often overshadowed by his brother Wenceslaus in terms of historical legacy. Certain medieval historians, notably Cosmas of Prague, overtly present Boleslaus as a cruel figure, particularly after the death of his brother. Over time, this perspective has evolved as modern historians have acknowledged his accomplishments as Duke through a more historically objective lens.

The crown of Saint Wenceslas (Czech: Svatováclavská koruna, German: Wenzelskrone) is a crown forming part of the Bohemian crown jewels, made in 1346. Charles IV, king of Bohemia and Holy Roman Emperor, had it made for his coronation, dedicating it to the first patron saint of the country St. Wenceslas and bequeathed it as a state crown for the coronation of (future) Bohemian kings. On the orders of Charles IV, the new royal crown was deposited in St. Vitus Cathedral, then later transferred to Karlštejn Castle. It was used for the last time in the coronation of Ferdinand V in 1836.