Wenceslaus was the son of Vratislaus I, Duke of Bohemia from the Přemyslid dynasty. His grandfather, Bořivoj I of Bohemia, was converted to Christianity by Cyril and Methodius. His mother, Drahomíra, was the daughter of a pagan tribal chief of the Havelli, but was baptized at the time of her marriage.

In 921, when Wenceslaus was about thirteen, his father died, and his grandmother became regent. Jealous of the influence that Ludmila wielded over Wenceslaus, Drahomíra arranged to have her killed. Drahomíra then assumed the role of regent and immediately initiated measures against Christians. When Wenceslaus was 18, those Christian nobles who remained rebelled against Drahomira. The uprising was successful, and Drahomira was sent into exile to Budeč.

With the support of the nobles, Wenceslaus took control of the government. He "...reined in the dependent dukes who had become restive under the regency and used Christianity to strengthen his state.”

Wenceslaus introduced German priests into his realm and favoured the Latin rite instead of the old Slavic, which had gone into disuse in many places for want of priests. He also founded a rotunda consecrated to St. Vitus at Prague Castle in Prague that was the basis of present-day St. Vitus Cathedral.

In September 935, a group of nobles allied with Wenceslaus's younger brother Boleslav plotted to kill him. After Boleslav invited Wenceslaus to a celebration of the feast of Saints Cosmas and Damian in Stará Boleslav, three of Boleslav's companions (Tira, Česta, and Hněvsa) fell on the duke and stabbed him to death.

Wenceslaus was considered a martyr and saint immediately after his death, when a cult of Wenceslaus grew up in Bohemia and in England.[14] Within a few decades, four biographies of him were in circulation. These hagiographies had a powerful influence on the High Middle Ages concept of the rex justus (righteous king), a monarch whose power stems mainly from his great piety as well as his princely vigor.

Although Wenceslaus was only a duke during his lifetime, Holy Roman Emperor Otto I posthumously "conferred on [Wenceslaus] the regal dignity and title", which is why he is referred to as "king" in legend and song.

Other Saints of the Day
1. Saint Lorenzo Ruiz
2. Saint Annemund
3. Saint Eustochium
4. Saint Faustus of Riez
5. Saint Mark