Saint Wenceslaus (feast day: Sept. 28), also known by Vaclav or Vaclavor, was born near Prague around 903, and was the son of Duke Wratislaw. He is the patron saint of Bohemia, parts of the Czech Republic, and was the duke of Bohemia from 922 until his death in 929 (or 936, or 1038.. there seems to be some confusion about the dates in question). He was taught Christianity by his grandmother, St. Ludmila. The Magyars, along with Drahomira (Wenceslaus' mother), an anti-Christian faction murdered the Duke and St. Lumila, and took over the government. Wenceslaus was declared the new ruler after a coup in 922. He encouraged Christianity, through German missionaries, building of churches, and perhaps by taking a vow of poverty and/or chastity.
In 929 the German king Heinrich I ("the Fowler", r. 919-936) invaded Bohemia and forced Wenceslaus to submit to his rule. Wenceslaus also supported Heinrich I as the rightful Charlemagne, to avoid being crushed by the Germans. This, along with his pro-Christian policies, led a group of non-Christian nobles to conspire against him. On September 28, 929, a group of knights under the leadership of Wenceslaus' brother Boreslav assassinated the saint on the doorstep of a church. Virtually from the moment of his death, Wenceslaus was considered a martyr and venerated as a saint. Miracles were reported at his tomb, and his remains were translated to the church of St. Vitus in Prague which became a major pilgrimage site. The feast has been celebrated at least since 985 in Bohemia, and he is best known from the Christmas carol "Good King Wenceslas."
http://www.newadvent.org/cathen/15587b.htm
http://www.catholic.org/saints/saint.php?saint_id=2040
http://www.roca.org/OA/45/45f.htm
http://www.kyberco.com/Rotasolis/wencesla.htm